Is this weather normal in Washington County?

Illinois · county records since 1895, through September 2026.

Weather › Illinois › Washington County

Washington County just had its warmest September ever recorded, +8° against the usual. Washington County has warmed about 0.5° per decade since 1970.

This week

Usual for Oct 28 to Nov 3: highs near 62°, lows near 40°

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

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usual high for the datewarmercooler

The last 12 months

Oct: +4.8°OctNov: +1.8°NovDec: 0.0°DecJan 2026: -2.1°JanFeb: +2.1°FebMar: +8.2°MarApr: +7.4°AprMay: -1.1°MayJun: +0.3°JunJul: +1.8°JulAug: +1.5°AugSep: +7.9°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: +1.2 inOctNov: -1.8 inNovDec: -1.9 inDecJan 2026: -2.2 inJanFeb: -1.3 inFebMar: +1.8 inMarApr: -0.4 inAprMay: -0.8 inMayJun: -0.8 inJunJul: -0.6 inJulAug: +0.1 inAugSep: -2.4 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 Washington County

MonthUsual high / lowUsual rainWarmestColdest
January40° / 23°2.9 in41.6° 200614.1° 1977
February45° / 27°2.4 in45.0° 201720.6° 1978
March55° / 35°3.7 in58.2° 201229.4° 1960
April67° / 45°4.9 in63.2° 202646.0° 1907
May76° / 55°5.1 in72.7° 201858.4° 1924
June85° / 64°4.6 in80.6° 195267.2° 1903
July88° / 67°3.9 in84.3° 201272.0° 2014
August87° / 65°3.3 in83.3° 193669.2° 1915
September81° / 57°3.4 in76.6° 202660.8° 1918
October69° / 46°3.3 in65.2° 196349.3° 1925
November55° / 36°3.9 in53.2° 190936.5° 1976
December44° / 27°2.9 in45.1° 202121.3° 2000

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

Towns in Washington County

Nearby counties