Jun 05 | Climate Review and Weather Update

We wrapped up spring and started meteorological summer with some lovely, if a bit drier, weather. Average temperatures this week ranged from the low 60s in northern Illinois to the mid-70s in southern Illinois, between 1 and 4 degrees above average. Low humidity allowed daytime temperatures to regularly reach into the upper 80s, while nighttime temperatures cooled well into the 50s. Some of the more impressive nighttime lows this week included 44 in Waukegan and 45 in Normal. It’s not often that we have dewpoint temperatures in the 30s and 40s, making for some very comfortable evening weather.

The downside to lower humidity is a lack of precipitation, and this week largely continued our dry stretch across much of the state. Rain totals from this week ranged from a big goose egg in most of northern Illinois to just under 3 inches in southwest Illinois. Following a very wet start to spring, the last 30 days have been exceptionally dry north of Interstate 70, with some parts of northern Illinois having less than 25% of normal rainfall since early May. Soil moisture and streamflow have declined rapidly in much of northern and central Illinois, resulting in moderate drought in this week’s U.S Drought Monitor.

Looking ahead, our weather will stay warm but the summer humidity is going to move in. High temperatures will be in the 80s this weekend and early next week before climbing well into the 90s by week’s end. Dewpoint temperatures will be in the 60s and 70s, making it feel much more like a typical Illinois summer. The higher humidity also comes with a more disturbed pattern, with moderate chances of showers and thunderstorms almost every day next week. Forecasted 7-day rain totals are over an inch for the entire state. Further out, outlooks for the middle part of June show warmer and wetter weather will stick around.