If you found yourself wondering during July’s hot and steamy weather why it seems as if it’s been a while since we’ve had a real summer heat wave, you’re right.
Northern Illinois has been blessed for the past several years – or cursed for those of you who like it hot – with milder temperatures, save for a few days of uncomfortable heat. But last month’s long heat spell hasn’t been felt in a while, state climatologist Jim Angel said.
“It has been [hot], especially when you factor in the humidity, and the fact that the first week of July was on the cool side,” Angel said.
The last time northern Illinois experienced prolonged hot summer temperatures was in 2012, when the state and much of the Midwest were gripped by a strong drought. It was followed in 2013 by a cooler-than-average summer for the eastern U.S., and summers in 2014 and 2015 likewise didn’t have prolonged heat streaks.
While high temperatures reached the mid-80s and mid-90s in late July, the lows at night never dipped below 68 degrees during the two-week period between July 18 and 30, according to National Weather Service measurements at O’Hare International Airport. It was only the second time since 2000 that such a streak took place, the last time being roughly the same part of late July 2011.
Fortunately, last month’s heat wave did not come with 2012’s crippling drought. Angel said the statewide average of 7.12 inches made last month the third wettest July on record, edging out a record that was 101 years old.
The second half of July also happened to be the wettest two-week period in three years – Rockford received almost 7.9 inches between July 5 and month’s end. But northern McHenry and Lake counties have been a bit drier than the state average, Angel said. McHenry County’s farmers are hoping for more rain – the Midwest Regional Climate Center’s station in Harvard recorded less than 10 inches of rain from April through July, compared with almost 20 during the same period last year.
Only a small sliver of far western Illinois is facing slight drought conditions – the rest of the state has had adequate precipitation, according to the U.S. Drought Monitor run by the University of Nebraska-Lincoln.
As for the rest of the summer, the National Oceanic and Atmospheric Administration Climate Prediction Center predicts that August’s temperatures could go any way – hotter, colder or average – for northern Illinois. The entire continental U.S. and Alaska could see a warmer fall than average if La Niña, a cooling of the equatorial Pacific Ocean that affects fall and winter temperatures and precipitation in North America, shows up. Predictions also project more precipitation than usual for northern Illinois should the phenomenon appear.
The forecast calls for temperatures in the mid-80s to low-90s throughout the workweek, with chances for storms throughout. A slight chance exists Tuesday that some storms could be severe.