What is the hottest month in Donnellson, IL?

July is the warmest month, with a normal high of 89°F at Hillsboro.

What is the coldest month in Donnellson, IL?

January is the coldest month, with a normal low of 21°F.

What is the wettest month in Donnellson, IL?

May has the most precipitation on average, about 5.06 inches.

Checked Oct 25, 2026

Donnellson, IL Climate

1991 to 2020 normals at Hillsboro, 9.1 mi from the center of Donnellson, elevation 630 ft.

Average weather by month

Select a month for daily normals and last year's weather

Month	High	Low	Precip.	Snow
January	38°	21°	2.52 in	--
February	45°	25°	2.61 in	--
March	55°	34°	3.05 in	--
April	68°	44°	5.03 in	--
May	78°	54°	5.06 in	--
June	86°	63°	3.83 in	--
July	89°	67°	3.74 in	--
August	87°	65°	3.14 in	--
September	82°	57°	3.30 in	--
October	70°	46°	3.41 in	--
November	55°	35°	3.76 in	--
December	43°	26°	2.62 in	--
Year	66°		42.07 in	--

Frequently asked questions

What is the hottest month in Donnellson, IL?: July is the warmest month, with a normal high of 89°F at Hillsboro.
What is the coldest month in Donnellson, IL?: January is the coldest month, with a normal low of 21°F.
What is the wettest month in Donnellson, IL?: May has the most precipitation on average, about 5.06 inches.

Today

Donnellson, IL forecast

Data sources

U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information · Official site
U.S. Climate Normals 1991-2020 (daily) and GHCN-Daily via Access Data ServiceNOAA National Centers for Environmental Information · Official site

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About this data

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Climate normals are 30-year averages measured at one weather station, which may be miles from the place named here or at a different elevation.

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