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St. Charles, MO weather and climate

St. Charles County, MO · population 71,048 · about 551 ft elevation

Everything below is a 30 year average for 1991-2020, computed from daily climate history at St. Charles's own coordinates.

The year at a glance

Sunny days
202
clear or partly cloudy, per year
Precipitation
41 in
per year
Wet days
118
rain or snow per year
Snowfall
10 in
per year
Hot days
35
above 90 °F
Freezing nights
104
at or below 32 °F
Humidity
69%
average relative
Average temperature
56 °F
year round

Monthly temperatures

Average daily high and low for each month, in °F.

Daily highDaily low
20406080JanMarMayJulSepNovDaily high, Jan: 40 °FDaily high, Feb: 45 °FDaily high, Mar: 55 °FDaily high, Apr: 67 °FDaily high, May: 76 °FDaily high, Jun: 84 °FDaily high, Jul: 88 °FDaily high, Aug: 87 °FDaily high, Sep: 80 °FDaily high, Oct: 69 °FDaily high, Nov: 55 °FDaily high, Dec: 44 °FDaily low, Jan: 22 °FDaily low, Feb: 25 °FDaily low, Mar: 34 °FDaily low, Apr: 44 °FDaily low, May: 55 °FDaily low, Jun: 64 °FDaily low, Jul: 68 °FDaily low, Aug: 66 °FDaily low, Sep: 57 °FDaily low, Oct: 46 °FDaily low, Nov: 35 °FDaily low, Dec: 26 °F
View monthly temperatures as a table
Monthly temperatures (°F)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Daily high404555677684888780695544
Daily low222534445564686657463526

Monthly precipitation

Total rain plus melted snow for each month, in inches.

0.02.04.0JanMarMayJulSepNovSt. Charles, Jan: 2.6 inSt. Charles, Feb: 2.4 inSt. Charles, Mar: 3.7 inSt. Charles, Apr: 4.5 inSt. Charles, May: 4.9 inSt. Charles, Jun: 4.0 inSt. Charles, Jul: 3.3 inSt. Charles, Aug: 2.9 inSt. Charles, Sep: 3.2 inSt. Charles, Oct: 3.3 inSt. Charles, Nov: 3.6 inSt. Charles, Dec: 2.5 in
View monthly precipitation as a table
Monthly precipitation (inches)
CityJanFebMarAprMayJunJulAugSepOctNovDec
St. Charles2.62.43.74.54.94.03.32.93.23.33.62.5

Monthly sunny days

Days each month with clear or partly cloudy skies.

01020JanMarMayJulSepNovSt. Charles, Jan: 14 daysSt. Charles, Feb: 13 daysSt. Charles, Mar: 15 daysSt. Charles, Apr: 15 daysSt. Charles, May: 16 daysSt. Charles, Jun: 17 daysSt. Charles, Jul: 21 daysSt. Charles, Aug: 22 daysSt. Charles, Sep: 21 daysSt. Charles, Oct: 19 daysSt. Charles, Nov: 17 daysSt. Charles, Dec: 14 days
View monthly sunny days as a table
Monthly sunny days (days)
CityJanFebMarAprMayJunJulAugSepOctNovDec
St. Charles141315151617212221191714

Compare St. Charles with another city

Nearby cities and popular picks. Any two cities can be compared from the home page.

See weather for every covered Missouri city

About this data

Figures are 30 year averages for 1991-2020. Wet days count days with measurable precipitation, calibrated against the wet day counts in NOAA's published climate normals. Sunny days count clear plus partly cloudy days, defined as average cloud cover of 63 percent or less and calibrated against NOAA's published sky cover tables. Snowfall figures are model estimates anchored to NOAA station measurements near each city.

Weather data by Open-Meteo.com (CC BY 4.0). Contains modified Copernicus Climate Change Service information (ERA5, ERA5-Land).