Full forecast details at the WGN Weather Center
Chicago enters a noticeably cooler, less humid weather regime this week – compared to last.
Monday’s muggy dew points and humidities are going away in the coming week, not to return until the coming weekend. Dew points, a measure of atmospheric moisture, will fall back to the low and mid 40s to low 50s. The exception is a brief spike into the low 60s Wednesday night and early Thursday.
That’s we’re anticipating dew points in the 40s this time of year, known for its often elevated humidities, are really interesting. It’s like bringing North Woods autumn air into the area despite the fact we’re still in summer.
This work week’s temps will average 9-degrees cooler than last, coming in at 70.8-deg, a reading nearly 4-deg below normal.
Drier weather dominates this work week, a big change from the drenching weekend rains which topped 3″ in some south suburban areas with nearly 12″ down the past 3 days in Stephenson County, IL to the west of Rockford.
Rain and t-storms are not to re-enter Chicago’s weather scene until over the coming weekend.
Cooler weather later in the week
The coming week’s coolest weather will ride well organized northeast winds into the area Thursday into Friday–winds likely to churn Lake Michigan and produce waves and rip currents at that time. The cool air accompanies a late summer high pressure system out of Canada. It’s frontside “NNE” winds are likely to ride south into Chicago the full length of Lake Michigan—the sort of set up known to generate the most noticeable increase in waves
Lengthy stretch of below average temps
Every one of the coming 15 days will average at or below normal–a distinct change from August’s open 7 of 8 days of which have finished above normal –that 88% of them!
It marks quite a change from August’s opening 7th days which have ranked 8th warmest of the past 151 years (since 1871). The month’s opening days are currently carrying a 4.6-deg surplus.
Extended outlook for Chicago area
And a second week of below normal temps continues next week–a week with temps just over a degree milder than this week but still come in nearly 2-deg below normal
Normal temps have begun a very slow seasonal decline. Normal highs and lows for Aug 8 average 83 and 65. By the end of next week, normals fall back to 82 and 65.