Climate averages 1991–2020
Naperville weather
in July.
A warm, wet month: the warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
July is a warm month in Naperville: daytime highs average 27.8°C and nights cool to about 18.9°C. By daytime temperature it is the warmest month of the year.
Expect about 94 mm of rain on roughly 11 days, which makes July a wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 53 min on an average July day.
The nearest other city in this atlas is Bolingbrook (12 km away). In July its highs average 27.8°C, about as warm as Naperville, with 95 mm of rain.
Among the 498 cities listed in the United States, Naperville ranks joint 366th of 498 for the warmest July highs and joint 341st of 498 for the driest July (rainfall, lowest first). The mean July high of those 498 cities is 30.3°C; Naperville is 2.5°C cooler than that mean.
From July to August, average highs fall by 0.9°C to 26.8°C, and monthly rainfall falls from 94 mm to 92 mm.
The annual picture
July 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
Naperville climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -0.8°C-8.6°C | -8.6°C | 54 | 8.1 | 9.510 h |
| February | 1.7°C-7.1°C | -7.1°C | 50 | 7.1 | 10.611 h |
| March | 7.8°C-1.6°C | -1.6°C | 68 | 9.6 | 11.912 h |
| April | 14.4°C4.2°C | 4.2°C | 113 | 11.8 | 13.313 h |
| May | 20.4°C10.5°C | 10.5°C | 117 | 12.7 | 14.515 h |
| June | 25.6°C16.2°C | 16.2°C | 108 | 11.7 | 15.215 h |
| July, selected | 27.8°C18.9°C | 18.9°C | 94 | 11.2 | 14.915 h |
| August | 26.8°C18.2°C | 18.2°C | 92 | 10.5 | 13.914 h |
| September | 23.1°C14.3°C | 14.3°C | 77 | 8.3 | 12.513 h |
| October | 16.2°C7.9°C | 7.9°C | 80 | 9.1 | 11.111 h |
| November | 8.5°C1.0°C | 1.0°C | 64 | 8.1 | 9.910 h |
| December | 2.1°C-4.9°C | -4.9°C | 55 | 8.0 | 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
July in nearby cities
- Bolingbrook in JulyUnited States · 12 kmHigh 27.8°C · Low 18.8°C · 95 mm rain
- Aurora (Illinois), United States in JulyUnited States · 15 kmHigh 27.8°C · Low 18.7°C · 94 mm rain
- Schaumburg in JulyUnited States · 28 kmHigh 27.7°C · Low 18.8°C · 90 mm rain
- Joliet in JulyUnited States · 29 kmHigh 28.2°C · Low 19.1°C · 95 mm rain
- Elgin in JulyUnited States · 30 kmHigh 27.8°C · Low 18.9°C · 94 mm rain
- Cicero in JulyUnited States · 33 kmHigh 27.8°C · Low 19.6°C · 92 mm rain
- Arlington Heights in JulyUnited States · 36 kmHigh 27.4°C · Low 19.5°C · 90 mm rain
- Chicago in JulyUnited States · 42 kmHigh 27.3°C · Low 20.2°C · 92 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 Naperville) is explained once on the Naperville year overview and on the Sources, method and limits page.
Aurora (Illinois), United States lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.