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Mount Vernon, IL weather and climate

Jefferson County, IL · population 14,492 · about 535 ft elevation

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

The year at a glance

Sunny days
201
clear or partly cloudy, per year
Precipitation
44 in
per year
Wet days
118
rain or snow per year
Snowfall
10 in
per year
Hot days
22
above 90 °F
Freezing nights
108
at or below 32 °F
Humidity
67%
average relative
Average temperature
55 °F
year round

Monthly temperatures

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

Daily highDaily low
20406080JanMarMayJulSepNovDaily high, Jan: 38 °FDaily high, Feb: 44 °FDaily high, Mar: 54 °FDaily high, Apr: 65 °FDaily high, May: 74 °FDaily high, Jun: 83 °FDaily high, Jul: 86 °FDaily high, Aug: 85 °FDaily high, Sep: 79 °FDaily high, Oct: 68 °FDaily high, Nov: 54 °FDaily high, Dec: 43 °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: 67 °FDaily low, Aug: 65 °FDaily low, Sep: 57 °FDaily low, Oct: 45 °FDaily low, Nov: 34 °FDaily low, Dec: 26 °F
View monthly temperatures as a table
Monthly temperatures (°F)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Daily high384454657483868579685443
Daily low222534445564676557453426

Monthly precipitation

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

0.02.04.0JanMarMayJulSepNovMount Vernon, Jan: 3.3 inMount Vernon, Feb: 3.0 inMount Vernon, Mar: 4.1 inMount Vernon, Apr: 5.2 inMount Vernon, May: 5.1 inMount Vernon, Jun: 3.9 inMount Vernon, Jul: 3.4 inMount Vernon, Aug: 2.8 inMount Vernon, Sep: 3.0 inMount Vernon, Oct: 3.5 inMount Vernon, Nov: 3.8 inMount Vernon, Dec: 3.2 in
View monthly precipitation as a table
Monthly precipitation (inches)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Mount Vernon3.33.04.15.25.13.93.42.83.03.53.83.2

Monthly sunny days

Days each month with clear or partly cloudy skies.

01020JanMarMayJulSepNovMount Vernon, Jan: 14 daysMount Vernon, Feb: 12 daysMount Vernon, Mar: 15 daysMount Vernon, Apr: 16 daysMount Vernon, May: 16 daysMount Vernon, Jun: 18 daysMount Vernon, Jul: 20 daysMount Vernon, Aug: 22 daysMount Vernon, Sep: 21 daysMount Vernon, Oct: 20 daysMount Vernon, Nov: 16 daysMount Vernon, Dec: 13 days
View monthly sunny days as a table
Monthly sunny days (days)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Mount Vernon141215161618202221201613

Compare Mount Vernon with another city

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See weather for every covered Illinois 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).