Summer wasn't so hot after all
CHAMPAIGN — Champaign-Urbana's long, hot summer of 2012 wasn't really that hot.
It wasn't even as hot as the summer of 2011, according to the Illinois State Water Survey.
Based on the average temperature of 76.5 degrees in the June through August meteorological summer, 2012 tied for fifth place (with 1954 and 1913) among Champaign-Urbana's hottest summers.
The summer of 2011 was a wee bit warmer, with an average temperature of 76.6 degrees, good enough for No. 4.
"Last summer was just a bit warmer thanks to really high nighttime temperatures," said state climatologist Jim Angel of the Illinois State Water Survey.
Nationally, however, it was the third hottest summer since record keeping began in 1895, according to the National Oceanic and Atmospheric Administration. The average temperature in the 48 contiguous states between June and August was more than 74 degrees, more than 2 degrees above the 20th-century average.
The all-time toastiest summers locally were 1936 (78-degree average temperature), 1934 (77.7 degrees) and 1983 (76.9 degrees).
With 10 days of 100-degree or more readings in June, July and August, and 48 days of 90 degrees or above, the local average daily high this summer was unusually warm — 89.2 degrees — but low temperatures averaged out at a relatively pleasant 63.2 degrees.
And while July was extraordinarily hot, with an average temperature of 82.5 degrees — 7.5 degrees above normal — June and August were only slightly above normal. The average temperature in June was 72.5 degrees, three-tenths of a degree above normal, and the average temperature in August was 74.4 degrees, 1 degree above normal.
By another measure, however, this is the third-warmest summer locally.
Through Tuesday, Champaign-Urbana had accumulated 1,334 cooling-degree days during this air-conditioning season. The record year is 1934 with 1,345, followed by 1,335 in 1936.
But Angel said he is not as big a believer in using cooling-degree days to measure summer heat as he is in using heating-degree days to measure winter cold.
"There is a strong relationship between heating-degree days and heating costs. It's not as clear-cut with cooling-degree days," he explained. "Part of the reason is that in Illinois we may run the air conditioning because of the humidity as much as the heat.
"Also a lot of people are reluctant to turn on the air conditioning at the beginning of summer until it gets pretty warm. So we could accumulate cooling-degree days in the spring and it's meaningless."
In fact, this year there were 26 cooling-degree days in March, nine in April and 154 in May — all before the summer cooling season began.
The National Weather Service's climate prediction center says it is likely that temperatures throughout Illinois will remain above normal through November.