Charleston (IL) monthly weather averages

Average daytime temperature

The bar chart below shows the average monthly peak daytime temperatures at Charleston

Charleston average temperature chart (Celsius) Charleston average temperature chart (Fahrenheit)
Average monthly temperatures in Charleston (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 1 3.8 10.6 17.7 23.3 28.2 29.8 28.6 25.4 19 11.1 3.7
°F 33.8 38.9 51.1 63.9 74 82.7 85.7 83.4 77.7 66.1 52 38.6

Please note: these are the average peak daytime temperatures (usually around mid-afternoon) so do not show daytime / night highs and lows. To see the daily range of temperatures have a look at the temperature max / min chart below.

Average rainfall & rainy days

The graph below shows the average rainfall and number of rainy days per month.

Charleston monthly rainfall chart (mm) Charleston monthly rainfall chart (inches)
Average monthly rainfall in Charleston (mm and inches)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
mm 57 53 84 96 103 96 108 79 82 72 90 77
inches 2.3 2.1 3.3 3.8 4 3.8 4.2 3.1 3.2 2.8 3.6 3
Rainy days 10 9 12 12 11 9 9 8 8 8 10 11

Average annual rainfall in Charleston: 947.267mm (372.9 inches)

Average daily sunshine

The bar chart below shows the average daily sunshine hours in Charleston

Charleston average daily sunshine chart
Average daily sunshine Charleston
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Hrs sunshine 5.2 5.8 6.6 8 9.6 11 10.9 10.1 8.7 7.4 4.9 4.3

Day / night temperatures

The graph below shows the daily range of temperatures for each month.

Charleston average minimum / maximum temperatures (Celsius) Charleston average minimum / maximum temperatures (Fahrenheit)
Maximum and minimum daily temperatures in Charleston (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Min °C -8.3 -6.1 -0 5.8 11.4 16.4 18.5 17.2 13.3 7 1.3 -4.9
Max °C 1.3 4.1 10.9 18 23.6 28.5 30.1 28.9 25.7 19.3 11.4 3.9
Min °F 17.2 21.1 31.9 42.4 52.5 61.4 65.3 62.9 55.9 44.5 34.3 23.2
Max °F 25.7 30.2 41.7 53.4 63.5 72.3 75.7 73.4 67.1 55.6 43.3 31.1

Sea temperature

The graph below shows the average sea temperature.

Charleston average sea temperature chart (Celsius) Charleston average sea temperature chart (Fahrenheit)
Average sea temperature around Charleston in degrees centigrade and fahrenheit
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 8.6 8 8.3 9.5 11.8 15.3 19.6 22.4 20.8 16.2 12.6 10.1
°F 47.5 46.4 46.9 49.1 53.2 59.6 67.2 72.3 69.4 61.2 54.6 50.2

Wind speed

The graph below shows the average wind speed.

Charleston average winspeed by month (km/h) Charleston average winspeed by month (mph)
Average wind speed in Charleston (mph and kmh)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
km/h 18 18 20 19 16 14 13 12 13 15 17 18
mph 11 11 12 12 10 9 8 8 8 9 11 11

A monthly average windspeed of over 16km/h or 10mph suggests a location is fairly windy.

Relative humidity

The graph below shows the average relative humidity.

Charleston relative humidity averages
Average relative humidity in Charleston
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
74% 73% 70% 65% 67% 67% 71% 73% 73% 69% 73% 77%

Other monthly averages

UV index Best time to go?

Charleston weather stats

Charleston weather statistics
Hottest month: July 29.8°C 85.6°F
Driest month: February 53mm 2.1ins
Sunniest month: July 10.9hrs
Coldest month: January 1°C 33.8°F
Wettest month: July 108mm 4.3ins
Warmest sea: August 22.4°C 72.3°F
Map showing location of Charleston (39.49615, -88.17615) Charleston map pin © Google

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