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Ten-day high temperature graph starting Tuesday, Aug. 12.
CHICAGO – Another scorching hot weekend is expected to engulf most of the Midwest starting on Friday.
Earlier this summer, we took a look at how the year 2025 stacked up against the last 67 years in Chicago.
Specifically, we dove into how many days during a given year that we can expect the daily high temperature to reach 90 degrees or hotter.
Since July 21, we have added seven more 90-degree days, bringing the total to 25 days.
The year of 2025 in Chicago has already exceeded the last four years in terms of 90-degree days. According to this criteria, the summer of 2025 ranks among the top 20% hottest summers in Chicago.
The data analyzed was sourced from O’Hare International Airport, where their weather station has kept a data log of weather variables since 1959.
Stats at a glance
- Average number of 90+ degree days per year : 17 days
- Year with most 90+ degree days : 1988 (47 days)
- Year with the least 90+ degree days : 1967, 2004, and 2014 (3 days)
- 90+ degree days so far in 2025 : 25 days
Looking forward
The average last day that Chicagoans see a high temperature reaching 90 degrees is Aug. 30. Thus, about one-fifth of the summer remains, and at our current pace, Chicago could see about seven more 90+ degree days bringing our expected grand total to 32 days.
Only 1983, 1987, 1988 and 2012 currently outpace the total number of 90+ degree days that we’ve seen so far in 2025. It is important to note that this is a purely statistical analysis and does not factor in the influence of current meteorological observation or forecast.
According to the Climate Prediction Center’s 3 – 4 week Temperature Outlook, Chicago is forecast to have equal chances of seeing temperatures above or below the climatological average temperature (~80°).
This year will probably not break any records, but with another heat wave approaching this weekend, 2025 will surely rank high on the all-time list in recorded history at O’Hare.
As our daylight dwindles and autumn approaches, it is important to keep in mind that September on average sees two 90+ degree days, specifically in Chicago.