30-year climate normals

Clinton County Climate and Weather Averages

Hottest month — July

88.3°

average daily high. The coldest month is January, averaging a low of 21.5°F.

Clinton County gets 45.86" of precipitation a year, and 33% of it falls in Apr, May, Jun.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	39.1°	21.5°	3.05"
February	44.8°	24.9°	2.45"
March	54.8°	34.5°	3.67"
April	66.6°	44.8°	4.90"
May	75.9°	55.9°	5.23"
June	84.8°	64.9°	4.87"
July	88.3°	68.1°	4.24"
August	87.4°	66.2°	3.59"
September	81.0°	58.1°	3.65"
October	69.5°	46.3°	3.39"
November	55.1°	35.5°	3.72"
December	43.3°	26.3°	3.10"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 33% falling in the wettest three months (Apr, May, Jun).

January 3.05"

February 2.45"

March 3.67"

April 4.90"

May 5.23"

June 4.87"

July 4.24"

August 3.59"

September 3.65"

October 3.39"

November 3.72"

December 3.10"

Annual total 45.86"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 1,438

Heating degree days How much heating the climate demands 4,780

Approximate annual cooling cost At 23.85¢/kWh, Illinois average $343

Approximate annual electric heating cost Lower where heating is gas rather than electric $399

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Clinton County, where electricity is one line of eight.

Common questions

What is the weather like in Clinton County?

Clinton County averages a high of 88.3°F in July and a low of 21.5°F in January. Annual precipitation is 45.86 inches, with essentially no snow.

When is the rainy season in Clinton County?

The wettest stretch is Apr, May, Jun, which accounts for 33% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Clinton County?

The average daily high in July, the hottest month, is 88.3°F. That drives 1,438 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Clinton County?

Effectively no. Measurable snowfall is rare in Clinton County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station CARLYLE RSVR, IL US (USC00111290), 3.6 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, Illinois residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.