CHAMPAIGN — Champaign-Urbana has entered what is historically the coldest two-week period of winter, but there's still no sign of subzero temperatures.
Monday was the 704th consecutive day without subzero temperatures, according to state climatologist Jim Angel at the Illinois State Water Survey. The last subzero reading in Champaign-Urbana was on Feb. 10, 2011, when the temperature plunged to -12.
The local record for consecutive days above zero degrees is 1,071 days — from Jan. 24, 1937, to Dec. 30, 1939.
The coldest reading so far this winter was 6 degrees on Jan. 2, and meteorologist Matt Barnes at the National Weather Service in Lincoln said there's no sign of anything colder through the end of the month.
"The chances of it happening are pretty slim at this point," said Barnes. "The trend is definitely for cold weather next week, though. The computer models show another chunk of cold Canadian air coming southward early next week and we may have high temperatures only in the teens at that time.
"But we're missing one important ingredient that would help us get to widespread below-zero temperatures. That's snow cover."
Most of the Midwest lacks any snow cover, Barnes said.
"When you have these cold air masses that are building up in Canada, where the sun is barely above the horizon, the best way to maintain that air mass is to have it slide southward over a snow cover. But this winter we have upstream of us, across Iowa and even Wisconsin, no snow on the ground. So the air masses that come out of Canada tend to be modified and warmed up by the time they get here," Barnes said.
Champaign-Urbana has received just 2.1 inches of snow this winter. Normal snowfall in November, December and January is about 14 inches.
December temperatures in Champaign-Urbana ran about 8 degrees above normal and so far January temperatures are about 5 degrees above average.
Weather statistics since 1981 show that the coldest period of the year is from Jan. 14 to Jan. 26 when the average daily high is 33 degrees and the average daily low is 16 degrees.
With no big snows on the horizon, Barnes said, it's likely that temperatures will be slightly colder than average but that no subzero days are forecast in January.
"It's too far out to really be confident about what will happen in February," he said. "For the next week or two it's definitely going to turn colder, but without that solid snow cover we can't expect widespread subzero temperatures."