Best year time to visit O'Fallon

General weather information about O'Fallon

Average annual temperature is 14.3 °C

Absolute maximum temperature: 37.6 °C

Absolute minimum temperature: -11.6 °C

Number of sunny days: 203 days

Number of rainy days: 162 days

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Absolute maximum temperature (°C)	20.2	19.9	22.5	27.5	31.5	34.4	37.6	37.0	32.5	29.5	26.6	17.6
Average daytime temperature (°C)	7.9	10.8	12.4	20.2	25.5	29.7	31.8	29.5	26.8	20.0	13.9	9.8
Average temperature (°C)	3.1	4.8	6.4	13.3	19.2	23.5	26.0	24.5	21.3	15.0	8.2	5.4
Average night temperature (°C)	-0.3	0.3	1.9	7.3	13.7	17.7	21.0	20.5	16.7	10.8	3.8	2.3
Absolute minimum temperature (°C)	-11.6	-10.6	-7.0	0.2	5.6	11.9	17.4	14.1	11.7	-2.0	-5.3	-5.7

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

The largest precipitation sum in O'Fallon is at

March — 192(mm)

May — 172(mm)

August — 188(mm)

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.