Waterloo (IL) monthly weather averages

Average daytime temperature

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

Waterloo average temperature chart (Celsius) Waterloo average temperature chart (Fahrenheit)
Average monthly temperatures in Waterloo (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 3.3 6 12.4 19.2 24.4 29.2 31.3 30.2 26.2 20.4 12.5 5.5
°F 37.9 42.8 54.4 66.6 75.9 84.6 88.4 86.4 79.1 68.7 54.5 42

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.

Waterloo monthly rainfall chart (mm) Waterloo monthly rainfall chart (inches)
Average monthly rainfall in Waterloo (mm and inches)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
mm 49 60 89 98 106 94 96 81 80 68 83 71
inches 1.9 2.4 3.5 3.8 4.2 3.7 3.8 3.2 3.1 2.7 3.3 2.8
Rainy days 9 9 12 11 10 9 9 8 8 8 10 10

Average annual rainfall in Waterloo: 921.634mm (362.8 inches)

Average daily sunshine

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

Waterloo average daily sunshine chart
Average daily sunshine Waterloo
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Hrs sunshine 5.6 6 6.9 8.1 9.4 10.6 10.8 9.7 8.6 7.5 5.2 4.7

Day / night temperatures

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

Waterloo average minimum / maximum temperatures (Celsius) Waterloo average minimum / maximum temperatures (Fahrenheit)
Maximum and minimum daily temperatures in Waterloo (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Min °C -6.5 -4.1 1.5 7.5 12.6 17.7 20 18.5 14.6 8.1 2.5 -3.4
Max °C 3.5 6.3 12.7 19.5 24.7 29.5 31.6 30.5 26.5 20.7 12.8 5.8
Min °F 20.3 24.7 34.7 45.5 54.6 63.9 68 65.3 58.2 46.6 36.4 26
Max °F 29.3 34 44.8 56.3 65.5 74.5 78.4 76.1 68.9 57.9 45.7 34.2

Sea temperature

The graph below shows the average sea temperature.

Waterloo average sea temperature chart (Celsius) Waterloo average sea temperature chart (Fahrenheit)
Average sea temperature around Waterloo in degrees centigrade and fahrenheit
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 10.3 9.8 10.4 11.8 14 16.6 19.7 22.6 21.2 17.1 13.9 11.7
°F 50.5 49.7 50.7 53.2 57.1 61.9 67.5 72.7 70.2 62.8 56.9 53

Wind speed

The graph below shows the average wind speed.

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

Waterloo relative humidity averages
Average relative humidity in Waterloo
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
73% 72% 68% 64% 67% 67% 69% 71% 72% 69% 72% 75%

Other monthly averages

UV index Best time to go?

Waterloo weather stats

Waterloo weather statistics
Hottest month: July 31.3°C 88.3°F
Driest month: January 49mm 1.9ins
Sunniest month: July 10.8hrs
Coldest month: January 3.3°C 37.9°F
Wettest month: May 106mm 4.2ins
Warmest sea: August 22.6°C 72.7°F
Map showing location of Waterloo (38.33589, -90.14983) Waterloo map pin © Google

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