This week in weather history we really begin to see the arrival of monsoon season and the heavy rains and flooding it can bring to the Thornton and Denver area.  Be sure to check out the events on the 23rd and what the heavy rain brought to the Thornton area in 2004.

1-31

In 2012…it was the hottest July on record in Denver since weather records began in 1872. The average temperature for the month was 78.9 degrees which was 4.7 degrees above normal. There were 27 days in which the high temperature equaled or exceeded 90 degrees…which established a new record. There were also 7 days in which the temperature equaled or exceeded 100 degrees which tied the record set in 2005.

7-25

In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks.  The record of 24 consecutive days was established in the summer of 2008.

13-5

In 2008…a streak of 26 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874.   Ironically…no new single day record high temperatures were set in the month of July. In august however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on august 2nd.

16-18

In 1997…an extended hot spell resulted in 3 temperature records being set. The maximum temperature reached 98 degrees on each of the days…setting records on the 16th and 18th. The low temperature of 71 degrees on the 17th was a record high minimum for the date. The high temperature reached 100 degrees on the 17th at the site of the former Stapleton International Airport.

18

In 1874…the temperature climbed to 90 degrees or more for the 18th consecutive day…setting a record. The record was equaled from July 6th through the 23rd in 1901.

In 1902…a thunderstorm produced northwest winds sustained to 45 mph with gusts to 48 mph along with rain and hail. Total precipitation was 0.53 inch.

In 1911…a shower produced north winds sustained to 44 mph.

In 1958…1 1/2 inch diameter hail fell 9 miles west-southwest of Stapleton Airport.

In 1981…a thunderstorm bombed Evergreen with about 2 inches of rain in 45 minutes. A heavy hailstorm left 5 to 7 inches of hail on the ground in some places and stopped the Colorado Open Golf Tournament at Hiwan.

In 1985…over 2 inches of rain doused the southwest suburbs of Denver. Street flooding occurred in the Montbello area of northeast Denver.

In 1992…nickel size hail fell across central Douglas County near Castle Rock and Sedalia. One inch diameter hail fell in Castle Rock.

In 1993…thunderstorm winds gusted to 60 mph at Strasburg east of Denver.

In 2004…heavy thunderstorm rainfall caused flooding over parts of the Virginia Canyon Road near Idaho Springs. Several sections of the roadway were washed out. The road was closed temporarily for repairs.

18-19

In 2003…heavy rain producing thunderstorms caused flash flooding across southern metro Denver.  Automated rain gages measured 2 to 3 inches of rain in less than an hour.  The heavy rainfall caused many intersections and underpasses to flood…stranding motorists.  Sections of I-25 and I-225 were closed due to the high water.

18-2

In 1987…a streak of 16 consecutive days of 90 degrees ranked 4th on the list of hot streaks.  The record of 24 consecutive days was established in the summer of 2008.

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In 1875…recent heavy rains produced high waters on many creeks and rivers in the area…which threatened the destruction of property at some locations.  Cherry Creek in the city was running the highest in 10 years.  Heavy rain in the mining regions over the last 2 days resulted in water running “everywhere” and the suspension of some work.

In 1881…a thunderstorm passing across the city produced lightning with no rain.  A woman was seriously injured when struck by lightning several blocks from the weather office in downtown Denver.

In 1934…the temperature reached a high of 100 degrees in downtown Denver.

In 1965…hail…rain…and lightning hit west metro Denver. Hail stones as large as 1 1/2 inches in diameter accumulated to a depth of 2 inches in Evergreen where 2.95 inches of rain in 2 hours caused some flooding in the business section of the town.  Lightning caused some power outages.

In 1973…two funnel clouds were observed 5 miles southeast of Littleton.  The same funnel clouds were observed for 20 minutes…5 miles west and 5 miles west-southwest of Arapahoe County airport…now Centennial Airport.

In 1975…lightning injured a man in Denver and caused power outages in Aurora…Lakewood…Westminster…and west Denver.

In 1984…strong thunderstorm winds gusting to 45 mph shattered 7 large plate glass windows at Stapleton International Airport.

In 1985…a tornado touched down in the surrey ridge area of northern Douglas County…just west of I-25.  Ten homes were damaged; one under construction was nearly destroyed.  Two vehicles were thrown off I-25 injuring three people.  A pick-up truck was thrown 50 feet by the twister.  In addition…a cluster of severe thunderstorms pounded all of metro Denver with torrential rain…hail…and wind.  The heaviest rain fell in Aurora where one location reported 2.37 inches in just 40 minutes.  One location in northeast Aurora received a total of 4.30 inches from the storm. There was extensive street and basement flooding…and a number of roads were damaged or washed out.  An Aurora boy suffered minor injuries when he was washed into a drainage ditch.  Golf ball size hail in Aurora piled up to 5 inches deep.  An inch of rain fell in 20 minutes at Stapleton International Airport…closing it to air traffic for an hour.  Up to 1 1/2 inches of rain fell in just 15 minutes over central Denver with the high water closing I-25.  The water was so deep on the freeway…that one vehicle was completely submerged and people were diving into the water from the freeway overpass.  Three homes in Littleton were damaged by lightning.  Wind blew out several windows from a high rise apartment building in southeast Denver. Rainfall totaled 1.51 inches at Stapleton International Airport.

In 1997…torrential rain and damaging hail pummeled eastern sections of metro Denver.  Hail up to 1.25 inches in diameter fell at the national weather service office on the site of the former Stapleton International Airport.  The hail continued for about 15 minutes and accumulated to a depth of 2 to 3 inches…causing extensive damage to cars in the area.  Heavy rainfall totaled 3.83 inches in about an hour from the nearly stationary thunderstorm.  Numerous cars stalled along I-70…and several homes were flooded in east Denver.  The roof of a building collapsed under the weight of the water.  The next day several “fatalities” were discovered near the national weather service office; two prairie dogs were found dead along with three rabbits that either drowned or were killed by the large hail.

In 1999…lightning struck two residences in Littleton…but caused only minor damage.  Lightning triggered a fire at a residence in cherry hills village.  A small portion of the roof and ceiling were damaged before the fire could be extinguished.

In 2000…hail as large as 1.25 inches in diameter fell near Roggen northeast of Denver.

In 2004…heavy rainfall caused flooding on the Virginia Canyon Road near Idaho Springs…which had to be closed for repairs.

In 2006…the temperature climbed to a high of 100 degrees.  The high temperature was not a record maximum for the date.

In 2007…a severe thunderstorm produced large hail…up to 1 inch in diameter…about 6 miles north of Northglenn.

In 2016…two men at the Indian Tree Golf Course in Arvada were struck by lightning when they sought shelter from a rapidly developing thunderstorm under a tree. One man died from his injuries while the other suffered minor injuries. Very heavy rainfall was observed across central and southern parts of Denver. The storm dropped around 1.5 inches of rainfall in 30 minutes and caused minor street flooding. Nickel size hail was reported west of Pine in central Jefferson County.

19-23

In 2005…the high temperature climbed above 100 degrees on each of the 5 days with readings of 101 on the 19th…105 on the 20th…104 on the 21st…and 102 on both the 22nd and 23rd. A new record maximum temperature for the month of July of 105 degrees was set on the 20th…which also equaled the all time record maximum for Denver of 105 degrees first set on august 8th in 1878.  Daily maximum temperature records were set on each day…and the 5 day period equaled the record for the most consecutive days of 100 degrees or more first set from July 4th through 8th in 1989.  The intense heat resulted in a high use of electricity for cooling purposes.  The demand for electric power exceeded the supply and rolling black-outs… Each lasting about an hour…were scheduled across metro Denver during the afternoons and early evenings.

» Click here to read the rest of July 18 to July 24: This week in Denver weather history

R & R! That is what in our forecast for a while. 😉 Until we return, please continue to use our website for the latest weather conditions, radar, forecasts and more.

As we move further into summer, we see a decrease in traditional things associated with severe weather like tornadoes.  However, there is a corresponding increase in heavy rain as Colorado gets closer to its monsoon season.  We see many occurences of dangerous flooding as well as damaging hail, deadly lightning and more as we look back at this week in Denver weather history.

1-18

In 1874…a streak of 18 consecutive days of 90 degrees tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.

1-31

In 2012…it was the hottest July on record in Denver since weather records began in 1872. The average temperature for the month was 78.9 degrees which was 4.7 degrees above normal. There were 27 days in which the high temperature equaled or exceeded 90 degrees…which established a new record. There were also 7 days in which the temperature equaled or exceeded 100 degrees which tied the record set in 2005.

6-23

In 1901…a streak of 18 consecutive days of 90 degrees tied for second with another streak set in the summer of 1874. The record of 24 consecutive days was established in the summer of 2008.

7-25

In 1934…a streak of 15 consecutive days of 90 degrees ranked 5th on the list of hot streaks.  The record of 24 consecutive days was established in the summer of 2008.

11

In 1872…heavy rainfall started at 4:00 pm and continued into the night.  The heavy rainfall damaged homes and buildings in all parts of the city.  Rainfall totaled 1.64 inches.

In 1888…the temperature reached 100 degrees in downtown Denver.

In 1954…the high temperature climbed to 102 degrees at Stapleton Airport.

In 1970…a girl walking in a park in southeast Denver received eye and facial injuries when lightning struck nearby.  Lightning also caused numerous power outages and heavy rainfall produced local flooding at several locations across metro Denver.

In 1974…large hail up to 1 1/2 inches in diameter fell in Thornton.

In 1990…the worst hailstorm in American history in terms of dollar damage at the time battered metro Denver.  Storm damage totaled 605 million dollars…as it cut a 5-to 10-mile wide swath from just southeast of Estes Park to northeast of Colorado springs.  Hail as large as baseballs (2.75 inches) pounded metro Denver.  Hardest hit areas were southeast Boulder County…the Jefferson County Airport in Broomfield… Arvada…east Wheat Ridge…southwest and south-central Westminster…west Thornton…northwest…west-central and downtown Denver…northeast and east-central Lakewood…just east of Littleton…portions of Arapahoe County west of I-25… And northern and central Douglas County near Castle Rock and franktown.  Golf ball to baseball size hail severely damaged roofs on thousands of homes and buildings…battered tens of thousands of automobiles…windows…signs…street lights…and traffic signals…stripped paint…awnings…and trim from buildings…punched holes in the roofs of two homes in Arvada…knocked out power and telephone service to thousands of homes and businesses…defoliated thousands of trees…ripped up greens and fairways on a number of golf courses…and severely damaged several aircraft tied down at Jefferson County Airport.  Hail the size of baseballs fell for several minutes in old town Arvada.  Later…golf ball size hail and heavy rain pummeled two northwest Denver amusement parks.  Hardest hit was Elitch Gardens amusement park where 47 people were injured and received treatment for bumps…cuts…and bruises at local hospitals.  Many of the injured were stranded on rides during the storm when power failed.  Hail clogged storm sewers…causing rain water to back up 3 to 6 feet deep on some roads and intersections in Arvada.  Several basements were flooded.  In some places hail was washed into drifts several feet deep.  In addition… The storm spawned 2 small tornadoes.  One touched down briefly in Lakewood near 6th avenue and Kipling Blvd….but did no damage.  In Castle Rock…a tornado (f1) did heavy damage to some homes and vehicles in the Founders Village development near Ridge Road.

In 2001…lightning struck two homes in Thornton.  Most of the damage was confined to the attics of both homes.  Hail as large as 3/4 inch in diameter fell in Keenesburg…Longmont… And near Boulder.

In 2015…a peak wind gust to 55 mph was measured from the northwest at Denver International Airport. A trace of rainfall was also observed.

11-12

In 1872…heavy rain from 4:00 pm until 2:00 am caused much damage.  Rainfall totaled 1.76 inches.

12

In 1881…during the early evening…a brisk rain fell for 30 minutes from a nearly clear sky containing not one tenth of clouds with the sun shining brightly.  Rainfall was 0.16 inch.

In 1885…thunderstorms produced widespread lightning across the city during the evening.  Several people were injured when their homes were struck by lightning.

In 1954…the high temperature reached 101 degrees at Stapleton Airport.

In 1962…lightning struck and killed a Denver man…while he was assisting a co-worker with his car.

In 1971…the temperature climbed to a high of 101 degrees at Stapleton International Airport.

In 1974…hail to 3/4 inch in diameter fell in Castle Rock.

In 1991…hail to 2 inches in diameter fell in Thornton with golf ball size hail in Brighton.  Dime size hail was recorded in the city of Denver.  Very heavy rain caused flooding across metro Denver.  Water was up to 2 feet deep in parts of Golden where one foot of water was reported in the lot of a mobile home park.  Flood water washed away part of a parking lot at the Colorado school of mines in Golden. Heavy rain caused a rock slide and flooding along I-70 in the foothills just west of Denver.  Flood waters were a foot deep at the intersection of I-70 and I-25 just north of downtown Denver.  A funnel cloud was sighted just east of the Rocky Mountain Arsenal.

In 1996…very heavy rainfall from a fast moving thunderstorm dumped 2 to 3 inches of rain within an hour over southern Jefferson County.  Two people were killed near the town of Buffalo Creek when a 20-foot wall of water flooded the area.  Utility poles and trees were uprooted; cars… Propane tanks…and bridges were destroyed in the flood’s path.  Entire buildings were moved from their foundations and heavily damaged by the floodwaters.  The first fatality occurred along State Highway 126 when the driver of a pick-up truck was washed off the road by the deadly wall of water.  The second death occurred farther upstream when a man in a 5th-wheel trailer was washed away.  This was the second disaster to strike the area in the last couple of months.  The community was already recovering from a wildfire which burned about 12 thousand acres of forest land in late May.  With the forest burned by fire…very little vegetation was available to slow the storm’s runoff…which resulted in the flash flood.  Power…water…and sewer service were heavily damaged in the flood and…in some cases…beyond repair.  The cost of repairing the roads and water system in the area was estimated at around a half million dollars.  Elsewhere across metro Denver…severe thunderstorms produced hail…damaging winds…and small tornadoes.  Weak tornadoes (f0) were reported in Broomfield… 3 miles east of Englewood…and in Dacono.  No damage was reported…except a trampoline was blown into a window and several trees were downed in Broomfield.  Thunderstorm wind gusts estimated as high as 60 mph blew a fence down in Louisville where winds also toppled a tree near a house. The house received only minor damage.  Large hail…strong winds and heavy rain caused substantial property damage in portions of southeastern Boulder and northern Jefferson counties.  Damage estimates in the Broomfield area alone were about 1 million dollars.  Winds gusted to 81 mph in Broomfield.  Large hail…3/4 to 1 1/2 inches in diameter fell in Evergreen…Lakewood…Englewood…Broomfield…near Morrison…northeast of Boulder…and just east of Denver International Airport.

In 2000…heavy rain fell across a portion of the Hi Meadow Fire burn area near Buffalo Creek…causing localized flooding.  About 3/4 inch of rain fell in 30 minutes over Miller Gulch.  Some culverts become plugged by debris from the fire.  As a result…small sections of a U.S. Forest Service road along Miller Creek were washed out.  Lightning struck a home in Castle Rock…causing extensive damage to the roof…attic…and second floor.

In 2011…severe thunderstorms developed over parts of Adams and Denver Counties. At Denver International Airport…a severe thunderstorm produced a peak wind gust to 66 mph… with another gust to 59 mph measured in Denver. In Commerce City…the intense winds blew down a large tree.

» Click here to read the rest of July 11 to July 17: This week in Denver weather history

One more hot day ahead with record-setting highs expected Friday. Tonight, a cold front moves in through that will cool us down for the balance of the period.

For today, look for a day much like we had yesterday. Mostly sunny skies will be above with just a bit of a chance for a PM storm. Highs will again push to, if not exceed, the 100 degree mark. Denver’s record high for today is 98 degrees and that will likely be broken. Tonight, any storms will end by sunset and we will see cloud cover increase as a cold front moves in. Overnight lows will be around 60 degrees.

Saturday will be the coolest day of the weekend with highs in the mid-80s. After some early cloud cover, skies will clear, then we have just a slight chance for afternoon thunderstorms. Saturday night into Sunday morning, skies will be mostly clear with lows in the upper 50s.

Sunday sees temperatures rebound just a bit. Highs will be in the upper 80s with sunny skies above. At this time, we do not expect any thunderstorms. Have a great weekend!

The question is, will we or won’t we hit the 100-degree mark today? The mercury will be rising and the potential is there.

The day starts out with sunny skies then we will see a few clouds as the morning progresses. Any clouds though will have minimal effect on the temperatures. Highs today will top out in the upper 90s, perhaps hit the century mark.

The afternoon brings just a slight chance for thunderstorms. However, any storms are expected to be widely scattered and not produce much more than gusty winds.

Tonight, skies will be becoming mostly clear with overnight lows in the mid-60s.

There isn’t a lot of narrative to add to a forecast for the weather we are to have today. It will be distinctly calm with lots of blue above and a bit warmer than average.

Sunny skies start us off and will be with us throughout the day. Overall conditions will be calm and dry. High temperatures will climb to the low to mid-90s.

Tonight, skies will remain clear with overnight lows in the low 60s.

A cold front is working its way toward us and will bring a short break from the heat. Some breezy winds and perhaps a thunderstorm will also be seen.

Partly cloudy skies start us off and will be with us throughout the day. High temperatures will be topping out in the low to mid-80s. Look for breezy winds this afternoon and some isolated thunderstorm activity.

Tonight, any storms will be ending soon after sunset. Skies will be clearing slowly with overnight lows in the mid-50s.

As we pointed out in our July weather preview, the month is not only our hottest but it is also the stormiest.  Scorching summer heat is certainly evident when we look back at this week in Denver weather history.  Perhaps more notable is the severe weather we have seen with everything from hail, damaging wind, dangerous lightning and deadly flooding having occurred.

29-15

In 2000…the 29th marked the beginning of a near record hot streak for metro Denver.  The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.

1-18

In 1874…a streak of 18 consecutive days of 90 degrees tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.

1-31

In 2012…it was the hottest July on record in Denver since weather records began in 1872. The average temperature for the month was 78.9 degrees which was 4.7 degrees above normal. There were 27 days in which the high temperature equaled or exceeded 90 degrees…which established a new record. There were also 7 days in which the temperature equaled or exceeded 100 degrees which tied the record set in 2005.

4

In 1874…the temperature reached a high of 102 degrees in downtown Denver.  Large forest fires in the mountains from the west-northwest to the south filled the atmosphere over the city with dense smoke.

In 1885…a thunderstorm produced sustained winds to 44 mph with gusts to 60 mph.  A circus tent was tattered by the strong winds.

In 1900…a thunderstorm produced northwest winds sustained to 42 mph with gusts to 51 mph…but only 0.05 inch of rain.

In 1903…the all time lowest temperature ever recorded in July…42 degrees…occurred. The temperature also occurred on July 31…1873.

In 1910…thunderstorm winds were sustained to 42 mph from the southwest.

In 1922…thunderstorm winds were sustained to 37 mph with gusts to 48 mph.

In 1956…a thunderstorm wind gust to 54 mph was recorded at Stapleton Airport.

In 1964…several men were knocked down by a bolt of lightning while playing golf in south metro Denver.  They got up and ran for cover when one of them was struck by a second bolt. He suffered burns and shock.

In 1987…a weak tornado was observed for 6 minutes…7 miles northeast of Watkins.  Hail 3/4 to 1 1/4 inches in diameter fell in southeast Aurora.

In 1988…lightning struck a group of people at the Jefferson County fairgrounds.  A 42-year-old woman was seriously injured and was hospitalized for 3 days.  Four other people sustained minor injuries.

In 1993…strong northwest winds uprooted several trees across metro Denver.  Wind gusts to 64 mph were reported at Erie north of Denver.  A west wind gust to 43 mph was recorded at Stapleton International Airport.

In 1995…lightning struck and injured two people standing in a field in Arvada.

In 1998…heavy thunderstorm rain…up to 2.75 inches…and marble size hail combined to flood local roads and fields near Roggen.

In 2002…heavy thunderstorm rain in the Hayman Fire burn area caused flash flooding.  In Jefferson County…gulch road was washed out.  In Douglas County…high water washed out some forest access roads as well…generally to the east of a line extending from Signal Butte to Deckers.

In 2010…intense thunderstorms produced torrential rainfall…  in excess of 5 inches in one hour…and caused flash flooding  in the vicinity of Elizabeth.  Numerous county roads were  washed out.  The combination of heavy rain and hail made it  necessary to run snow plows through town.  Extensive  basement flooding was also reported.  Severe thunderstorms  produced large hail from Aurora south to Elizabeth and  Larkspur.  The hail size ranged from 1 to 2 inches in  diameter.  A wet microburst produced 1.84 inches of rainfall  at Denver International Airport.  A peak wind gust to 48 mph  was also observed from the northeast.

In 2017…a microburst produced a wind gust to 61 mph…about 13  miles east-northeast of Denver International Airport.

4-5

In 1875…nearly every railroad running into the city was damaged by heavy thunderstorm rains.  The heavy rains washed out wooden bridges over normally dry creeks. Some trains were entirely suspended.  In the city…heavy thunderstorm rain totaled 1.05 inches on the 4th…but only 0.28 inch on the 5th.

4-8

In 1989…one of the most intense heat waves on record roasted metro Denver.  The temperature reached 100 degrees or more on 5 consecutive days.  The city had previously never recorded more than 2 straight 100-degree days since records began in 1872.  Water and electricity usage reached all time highs.  The heat wave created extremely dry weather conditions…which contributed to a major forest fire in Boulder canyon on July 9th.  The temperature reached 103 degrees on the 8th…and the mercury climbed to 101 degrees on both the 4th and 5th…and to 102 degrees on both the 6th and 7th.  The low temperature of 68 degrees on the 8th equaled the record high minimum for the date.

» Click here to read the rest of July 4 to July 10: This week in Denver weather history

Change is of course the one constant in Denver’s weather but come July, things actually get pretty consistent.

The standard formula for a day in July is a sunny morning, clouds developing in the late morning and early afternoon. Come mid-afternoon, thunderstorms are rolling off of the foothills and into the metro area and the eastern plains. These storms do occasionally reach severe status containing hail, gusty winds and heavy downpours of rain.

Check out our July weather preview for a complete look at what is in store for the month ahead.

Not too shabby of a holiday weekend for Thornton. Temps and conditions are going to be pretty typical for what we expect this time of year.

For Friday, with a good bit of moisture still around, partly sunny skies will be above. Temps will be topping out in the mid-80s. Some PM thunderstorm activity can be expected. Tonight, thunderstorms will end soon after dark and then skies will begin to clear. Overnight lows will be around 60 degrees.

Saturday brings back a good dose of sun for much of the day. Highs climb to around 90 degrees. The afternoon will see some scattered thunderstorm activity. Saturday night into Sunday morning, skies will be mostly clear with lows around 60 degrees.

The Fourth of July brings conditions much like the previous day. Sunny skies will be around early then some PM thunderstorm activity. Highs will again be around 90 degrees. At this time it appears any thunderstorms will be done before dark when the fireworks will begin flying.

Have a fantastic weekend and please be safe!