CHAMPAIGN — June marked the ninth consecutive month that temperatures in Champaign-Urbana were above normal.
But it wasn't nearly as extraordinarily warm as some past months. June highs were 2.6 degrees above normal, according to the Illinois State Water Survey, but lows were actually 2.4 degrees below normal. Overall temperatures were three-tenths of a degree above the average of 72.2 degrees.
The last month with below-average temperatures locally was September 2011. Since January 2011, only four months have recorded below-average temperatures.
The statewide average of 52.8 degrees for the last six months is the warmest on record, beating a similar period in 1921, when the statewide average temperature was 52.1 degrees.
There's no single reason for the run of warm weather, said Jim Angel, the state climatologist at the Illinois State Water Survey in Champaign.
"There isn't one particular thing that is responsible, at least that I've heard of," Angel said. "It's hard to point to one thing and say it's La Nina or El Nino or even global warming because this isn't a global or national occurrence."
Matt Barnes, a meteorologist at the National Weather Service office in Lincoln, agreed.
"We've just been in a persistent pattern where we've had a ridge of high pressure in place over the central and southern United States, and that's kept a large chunk of the country, not just here in Illinois, in above-normal temperatures," Barnes said. "About the only places where it's been cool from time to time would be in the Pacific northwest and the New England area.
"It's part of a larger-scale pattern and oftentimes these things last for several months before there's a major shift in it. And we don't see a big shift in the pattern through the rest of the summer. I don't think this is that uncommon."
There's a better-than-average chance that temperatures in downstate Illinois will be above normal in July, according to the Climate Prediction Center at the National Oceanic and Atmospheric Administration.
Statewide, the average temperature last month was 72.9 degrees, one degree above normal, according to the water survey. While the month was warm, it was far behind the hottest June on record: 1934 with a statewide average temperature of 78.5 degrees.
Total precipitation this year is running about 6 inches below normal. Champaign-Urbana has received 13.98 inches of rain and snow compared with the average of 19.95 inches.
Rainfall totalled just 2.28 inches last month, more than 2 inches below the June average of 4.34 inches. It was the fifth consecutive month of below-normal precipitation.
There's also a better-than-average chance of below-normal precipitation in the Midwest, the NOAA said, in an area centered in Illinois and including Indiana, Iowa and Missouri.
The highest temperatures in June were recorded on the 28th and 29th, when the thermometer reached 100 degrees. There were nine days when the temperature reached 90 degrees or above, all after June 15. The lowest temperature last month was 47 degrees on June 2.
Meanwhile, the weather service Monday issued an excessive-heat warning for the area through 7 p.m. Saturday.
"High temperatures will be in the upper 90s to around 100 across central and eastern Illinois through the period, with afternoon heat index values of around 105," the weather service said. "The hottest day is expected to be Wednesday as temperatures should be over 100 with Heat Index Values around 110."