Climate averages 1991–2020
Chicago weather
in May.
A mild, wet month: the 5th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Chicago: daytime highs average 18.7°C and nights cool to about 10.9°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 110 mm of rain on roughly 12 days, which makes May a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 31 min on an average May day.
The nearest other city in this atlas is Cicero (9 km away). In May its highs average 19.9°C, 1.2°C warmer than Chicago, with 110 mm of rain.
Among the 498 cities listed in the United States, Chicago ranks 457th of 498 for the warmest May highs and joint 400th of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; Chicago is 5.1°C cooler than that mean.
From May to June, average highs rise by 5.9°C to 24.6°C, and monthly rainfall falls from 110 mm to 102 mm.
The annual picture
May in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Chicago climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -0.7°C-7.4°C | -7.4°C | 62 | 9.1 | 9.510 h |
| February | 0.9°C-6.5°C | -6.5°C | 54 | 7.6 | 10.611 h |
| March | 6.0°C-1.6°C | -1.6°C | 71 | 10.3 | 11.912 h |
| April | 12.3°C4.4°C | 4.4°C | 114 | 12.4 | 13.313 h |
| May, selected | 18.7°C10.9°C | 10.9°C | 110 | 12.4 | 14.515 h |
| June | 24.6°C17.2°C | 17.2°C | 102 | 12.1 | 15.215 h |
| July | 27.3°C20.2°C | 20.2°C | 92 | 11.5 | 14.915 h |
| August | 26.4°C19.7°C | 19.7°C | 95 | 10.9 | 13.914 h |
| September | 22.7°C15.8°C | 15.8°C | 75 | 8.8 | 12.513 h |
| October | 15.9°C9.2°C | 9.2°C | 85 | 9.5 | 11.111 h |
| November | 8.4°C2.4°C | 2.4°C | 72 | 9.0 | 9.910 h |
| December | 2.2°C-3.5°C | -3.5°C | 61 | 8.7 | 9.29 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Cicero in MayUnited States · 9 kmHigh 19.9°C · Low 10.9°C · 110 mm rain
- Evanston in MayUnited States · 22 kmHigh 17.7°C · Low 11.0°C · 104 mm rain
- Hammond in MayUnited States · 32 kmHigh 19.5°C · Low 11.6°C · 113 mm rain
- Arlington Heights in MayUnited States · 38 kmHigh 19.2°C · Low 10.4°C · 110 mm rain
- Gary in MayUnited States · 38 kmHigh 19.3°C · Low 11.6°C · 112 mm rain
- Bolingbrook in MayUnited States · 39 kmHigh 20.6°C · Low 10.6°C · 113 mm rain
- Schaumburg in MayUnited States · 41 kmHigh 20.2°C · Low 10.1°C · 110 mm rain
- Naperville in MayUnited States · 42 kmHigh 20.4°C · Low 10.5°C · 117 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Chicago) is explained once on the Chicago year overview and on the Sources, method and limits page.
Cicero lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.