Is this weather normal in Grundy County?

Illinois · county records since 1895, through September 2026.

Weather › Illinois › Grundy County

Grundy County just had its warmest September ever recorded, +4° against the usual. Grundy County has warmed about 0.5° per decade since 1970.

This week

Usual for Oct 28 to Nov 3: highs near 57°, lows near 37°

That is the 1991 to 2020 average for these dates in Grundy County. The Weather Service forecast fills in below.

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usual high for the datewarmercooler

The last 12 months

Oct: +3.9°OctNov: +1.1°NovDec: -3.5°DecJan 2026: -2.4°JanFeb: +3.8°FebMar: +6.3°MarApr: +5.5°AprMay: -0.9°MayJun: -0.8°JunJul: +1.2°JulAug: +0.3°AugSep: +4.4°Sepwarmercooler

Each bar is a month's average temperature against the usual for that month (1991 to 2020). Ranks compare the same month in every year since 1895.

Every year since 1895

18952025

Rain and drought

Oct: -1.5 inOctNov: -0.4 inNovDec: +0.3 inDecJan 2026: -0.2 inJanFeb: -1.6 inFebMar: +1.3 inMarApr: +2.7 inAprMay: -2.5 inMayJun: +4.3 inJunJul: -1.4 inJulAug: +4.0 inAugSep: +0.7 inSepwetterdrier

Rain and melted snow against the usual for each month. The drought reading is NOAA's Palmer index for the county.

Month by month in Grundy County

MonthUsual high / lowUsual rainWarmestColdest
January32° / 16°2.1 in35.8° 20067.2° 1977
February36° / 20°1.8 in39.0° 199812.2° 1936
March48° / 29°2.3 in54.2° 201223.1° 1960
April62° / 39°3.6 in56.9° 201041.0° 1907
May73° / 50°4.6 in68.5° 197753.0° 1917
June82° / 60°4.5 in76.0° 193363.5° 1916
July85° / 64°4.0 in80.4° 201268.9° 2009
August83° / 62°3.8 in79.4° 194764.5° 1915
September77° / 54°3.3 in70.2° 202656.6° 1918
October65° / 42°3.1 in62.0° 196342.4° 1917
November49° / 32°2.5 in48.6° 200130.9° 1951
December37° / 22°2.0 in39.4° 201514.8° 1963

Warmest and coldest are the month's whole-month average temperature, with the year it happened.

Towns in Grundy County

Crime Radar: Channahon, Morris, Coal City, Braidwood, Dwight, Diamond

Nearby counties