Climate averages 1991–2020
Joliet weather
in May.
A mild, wet month: the 5th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Joliet: daytime highs average 21.2°C and nights cool to about 11.0°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 116 mm of rain on roughly 13 days, which makes May a wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 14 h 30 min on an average May day.
The nearest other city in this atlas is Bolingbrook (19 km away). In May its highs average 20.6°C, 0.7°C cooler than Joliet, with 113 mm of rain.
Among the 498 cities listed in the United States, Joliet ranks joint 331st of 498 for the warmest May highs and joint 429th of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; Joliet is 2.6°C cooler than that mean.
From May to June, average highs rise by 5.0°C to 26.3°C, and monthly rainfall falls from 116 mm to 110 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
Joliet climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -0.2°C-8.1°C | -8.1°C | 58 | 8.6 | 9.510 h |
| February | 2.4°C-6.5°C | -6.5°C | 51 | 7.2 | 10.611 h |
| March | 8.7°C-1.2°C | -1.2°C | 72 | 10.2 | 11.912 h |
| April | 15.4°C4.8°C | 4.8°C | 112 | 12.4 | 13.313 h |
| May, selected | 21.2°C11.0°C | 11.0°C | 116 | 12.5 | 14.514 h |
| June | 26.3°C16.6°C | 16.6°C | 110 | 11.7 | 15.115 h |
| July | 28.2°C19.1°C | 19.1°C | 95 | 11.3 | 14.915 h |
| August | 27.4°C18.5°C | 18.5°C | 93 | 10.2 | 13.814 h |
| September | 23.8°C14.5°C | 14.5°C | 75 | 8.3 | 12.513 h |
| October | 16.9°C8.2°C | 8.2°C | 81 | 9.2 | 11.111 h |
| November | 9.1°C1.4°C | 1.4°C | 69 | 8.6 | 9.910 h |
| December | 2.6°C-4.5°C | -4.5°C | 56 | 8.2 | 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
- Bolingbrook in MayUnited States · 19 kmHigh 20.6°C · Low 10.6°C · 113 mm rain
- Naperville in MayUnited States · 29 kmHigh 20.4°C · Low 10.5°C · 117 mm rain
- Aurora (Illinois), United States in MayUnited States · 33 kmHigh 20.7°C · Low 10.5°C · 117 mm rain
- Cicero in MayUnited States · 45 kmHigh 19.9°C · Low 10.9°C · 110 mm rain
- Hammond in MayUnited States · 49 kmHigh 19.5°C · Low 11.6°C · 113 mm rain
- Chicago in MayUnited States · 51 kmHigh 18.7°C · Low 10.9°C · 110 mm rain
- Schaumburg in MayUnited States · 57 kmHigh 20.2°C · Low 10.1°C · 110 mm rain
- Elgin in MayUnited States · 59 kmHigh 20.6°C · Low 10.4°C · 118 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 Joliet) is explained once on the Joliet year overview and on the Sources, method and limits page.