The last time one of the major political parties held a major part of their political convention outdoors was 48 years ago. On July 15, 1960 John F. Kennedy accepted his party’s nomination in the Los Angeles Coliseum before 50,000 people. Denver isn’t Los Angeles though and our weather is a lot more volatile than sunny southern California. As locals all know, the one thing consistent about Colorado weather is the inconsistency and that is true in the month of August.
As the end of the month comes, we start to notice our daylight hours getting fewer and even a bit of a chill in the early morning air. Historical temperature extremes for August are somewhat interesting. First, the highest temperature ever reached in Denver was actually recorded in August – 105 degrees on August 8, 1878 (also tied on July 20, 2005). Second, while there has never been snow in Denver in August, twice the mercury has dropped to 40 degrees to serve as a reminder the white stuff isn’t too far off – those occurrences were on August 22, 1904 and August 24, 1910.
On August 28th, the day Barrack Obama will accept the nomination, the normal high temperature is 83 degrees. Extremes? Our record high temperature for that day, set multiple times – most recently in 1969 – was 94 degrees. The lowest high temperature ever recorded on the 28th is 66 degrees in 1898.
Generally the chance for severe storms decreases in August but precipitation is not unusual at all. Cooler air near the surface helps to create a stable atmosphere thus keeping thunderstorms from usually becoming too intense. After the middle of August, tornadoes and damaging hail are pretty rare. The slow movement of storms this time of year are more likely to produce potentially heavy rain.
From midnight to noon convention visitors can usually expect clear conditions but it is the afternoon and evenings when things could get interesting. Those are the times when thunderstorms roll across the Front Range – typically 8 days a month have them, 9 with measurable precipitation.
Will weather be a factor for the DNC in 2008? We won’t know that until it gets closer but it could be interesting.