How hot was 2012? Hottest ever
CHAMPAIGN — If it seemed a little toasty around here last year, you are correct; 2012 was the warmest year in Champaign-Urbana weather history.
The mean temperature for the year was 55.7 degrees, almost a half-degree warmer than the previous record of 55.3 degrees in 1931, according to state climatologist Jim Angel at the Illinois State Water Survey.
And the yearly mean was more than 4 degrees above the average annual temperature of 53.6 degrees.
Nine months had above-average temperatures, led by March's astonishing 55-degree mean temperature, 15 degrees above normal. Five other months — January, February, May, July and December — had average temperatures more than 5 degrees above normal.
The only months with below-average temperatures were September, October and November.
"I thought that the below-normal temperatures in September, October and November had knocked us out of the chance for a record warm year, but December came roaring back with temperatures 8 degrees above normal," Angel said.
There were 10 100-degree or more days in June, July and August. The summer record is 15 100-degree days in 1936.
And with 55 days of 90 degrees or more, last year missed tying the record of 56 such days established in 1988, 1954 and 1936.
But July did set a new record for most 90-plus days in a month, 27. The average daily high temperature in July was 95.3 degrees, more than 10 degrees above average.
The nearly year-long heat and warmth was the result of a number of factors, according to a National Weather Service meteorologist.
"It can't easily be explained by one thing. There are several things in play," said meteorologist Matt Barnes, "but the most important thing was that our upper-air pattern for virtually the whole year, we had a ridge of high pressure across much of the Midwest, and that kept the main storm track well to the north and northwest of us.
"We never got as many storm systems across the area and we stayed warmer. As the year progressed we had that deficit of rainfall and that allowed the air to get even hotter than it normally would because of the lack of moisture. It kind of fed off the pattern already in place and made it more pronounced."
That pattern is still in place, Barnes said.
"The really cold, cold air, the stuff you would normally expect in wintertime is for the most part trapped up in northern Canada and in the other side of the world in Russia and Siberia," he said. "The jet stream pretty much drives the weather and the air masses. With that pretty much to the north, we're remaining on the warm side."
The private weather service, AccuWeather, on Monday forecast waves of brutally cold air later this month, possibly including a series of storms.
But Barnes said the government's Climate Prediction Center is forecasting warmer than normal temperatures in central Illinois and most of the rest of the country through January. The three-month projection for central Illinois, through March, forecasts equal chances of normal, above normal and below normal temperatures.
Statewide, 2012 was the second-warmest and 10th driest year on record. The statewide average temperature for 2012 was 55.5 degrees, 3.3 degrees above normal and second to 1921 (55.6 degrees) in terms of mean temperature. The statewide average precipitation for 2012 was 30.4 inches, 9.8 inches below normal and the 10th driest year on record in Illinois, according to the water survey.
Champaign-Urbana received 34.46 inches of precipitation last year, which is almost 7 inches below normal, but far short of the record for least precipitation, 24.68 inches in 1914.
The dry weather had one benefit, according to the National Weather Service in Lincoln.
"Severe weather occurrences were lower than normal due to dry conditions, with 14 tornadoes observed this year," said the weather service. The normal total for the 35-county Lincoln region is 16. Nine of the 14 tornadoes occurred on Aug. 31 and Sept. 1.
2012's snowfall total in Champaign-Urbana was far less than half the normal — 10.1 inches compared with the normal 23.2 inches. As meager as it was, the snowfall total was far short of the record in calendar year 2006, 3.3 inches, and it ranked only 11th-lowest overall.
Champaign-Urbana's mean monthly temperatures in 2012 and departure from normal
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