Best year time to visit O'Fallon

General weather information about O'Fallon

Average annual temperature is 14.5 °C

Absolute maximum temperature: 37.2 °C

Absolute minimum temperature: -11.5 °C

Number of sunny days: 198 days

Number of rainy days: 164 days

Number of snow days: 3 days

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* Weather data for O'Fallon United States is based on climate observations for 2026 year

O'Fallon air temperature forecast for each month

JanFebMarAprMayJunJulAugSepOctNovDec
Absolute maximum temperature (°C)19.621.123.028.031.734.937.037.232.329.926.317.6
Average daytime temperature (°C)8.111.312.920.725.830.231.429.727.120.414.09.9
Average temperature (°C)3.55.36.813.819.623.925.724.621.415.28.45.5
Average night temperature (°C)0.20.82.28.014.018.021.020.416.610.94.02.4
Absolute minimum temperature (°C)-11.5-10.2-6.80.86.112.316.913.811.3-2.0-5.2-6.1

O'Fallon monthly weather indicators

JanFebMarAprMayJunJulAugSepOctNovDec
Daylight maximum duration (h)10.011.012.013.014.014.014.014.013.011.010.09.0
Daylight mean duration (h)9.810.812.013.214.314.814.613.612.411.210.19.5
Daylight minimum duration (h)9.010.011.012.013.014.014.013.011.010.09.09.0
Sunshine mean duration (h)5.17.46.910.210.712.511.69.810.57.77.85.5
Precipitation (mm)767521279159548513977711989
Sunny days16161218171891319182418
Rainy days13121812141222181113613
Snow days201000000000

O'Fallon - weather forecast by months

O'Fallon weather in januaryO'Fallon weather in februaryO'Fallon weather in marchO'Fallon weather in aprilO'Fallon weather in mayO'Fallon weather in juneO'Fallon weather in julyO'Fallon weather in augustO'Fallon weather in septemberO'Fallon weather in octoberO'Fallon weather in novemberO'Fallon weather in december

Best time to visit O'Fallon:

The best time to visit O'Fallon during the most sunny months:

  • June — 12.5(h)
  • July — 11.6(h)

The largest precipitation sum in O'Fallon is at

  • March — 212(mm)
  • May — 159(mm)
  • August — 139(mm)

    • Weather forecast in the closest to O'Fallon admin centers

    Weather forecast in the closest towns to O'Fallon

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    Frequently asked questions

    When is the best time to visit O'Fallon?
    The historical weather data above shows the warmest, sunniest and driest months to help you choose the best time to visit O'Fallon.
    What is the weather like in O'Fallon?
    See average temperature, rainfall and daylight hours for O'Fallon by month in the table above.
    How many sunny days does O'Fallon have?
    The monthly weather statistics above show sunshine and rainfall patterns for O'Fallon throughout the year.