Construction weather days in Chicago, IL
About 67 rain days a year, month by month, from the NOAA station nearest Chicago: the baseline a weather-delay claim is measured against.
Rain days by month in Chicago, IL
Mean days with 0.10 in (2.5 mm) of rain or more, 2016–2025, NOAA GHCN-Daily station Chicago Midway Ap. 67 days a year.
What it means for a schedule
A project in Chicago should expect about 67 days a year with enough rain to count as a weather day under a 0.10 in rule. The wettest months are May, Jul, Apr (8, 7, 7 days); the driest are Jan, Feb, Dec. A contract that allows the mean number of weather days per month grants an extension only for the days above it, so the monthly baseline, not the annual total, is what a claim is measured against. Snow, freezing and wind rules add days on top of rain.
The weather-day tool takes your contract's own thresholds, gives the mean and 80th percentile for each month at the station nearest your site, and tracks actual weather days against that baseline every month, with a PDF for the claim file.
Nearby cities
Milwaukee · Indianapolis · Detroit · Louisville · Columbus · Nashville · all 30 cities
The same station networks feed EPW.tools' hourly EnergyPlus weather files (EPW) and design conditions for the building itself.
Frequently asked questions
How many rain days does Chicago, IL get a year?
About 67 days with 0.10 in of rain or more (2016-2025, NOAA station Chicago Midway Ap).
What is the wettest month in Chicago for construction?
May, with about 8 rain days on average.
Can I use my contract's own weather-day rules?
Yes. The weather-day tool takes any combination of rain, snow, cold, heat and wind thresholds, in US or SI units.
Is this enough for a time-extension claim?
It records the baseline and the actual days from the same NOAA station with the same rules; how days are counted is set by the contract.
Check your own site
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