inland destination · city of 29,002 · warmest in Jul · mid-range
Open O'Fallon on the live value map →| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg °C | -2 | 1 | 7 | 13 | 18 | 23 | 26 | 24 | 20 | 14 | 7 | 1 |
| High °C | 3 | 6 | 12 | 19 | 24 | 29 | 31 | 30 | 27 | 20 | 12 | 6 |
| Low °C | -7 | -4 | 1 | 7 | 12 | 17 | 20 | 18 | 14 | 7 | 2 | -4 |
| Rain (days) | 52 | 59 | 87 | 95 | 103 | 95 | 93 | 81 | 83 | 68 | 78 | 73 |
Warmest month: Jul. Driest: Jan.