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Monroe County, IL

: September 2026 so far averaged 77°F in Monroe County, IL, the warmest 1 to 29 September in the county average since the data begin in 1951 (county average from NOAA gridded data, 1951 to 2026).

Last updated . This page normally updates every day; the latest update is late.

High
81.5°F
Warmest since 2025
25th warmest of 76
Low
51.5°F
Warmest since 2025
34th warmest of 76

No measurable precipitation in the county average of Monroe County, IL for 7 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).

Every 29 September high of the county average in Monroe County, IL since 1951: 81.5°F in 2026; the highest is 99.3°F, in 1953.
2025: 87.6°F1953: 99.3°F2026: 81.5°F 2026 81.5°F 1953 99.3°F since 2025 1951 2026
  • Normal range, 68.4 to 85°F
Every year as a table

Every 29 September low of the county average in Monroe County, IL since 1951: 51.5°F in 2026; the lowest is 37.1°F, in 1951.

YearHigh, °FLow, °F
202681.551.5
202587.655.2
202474.464.7
202384.563.5
202267.840.5
202188.261.2
202068.446.9
201985.467.9
201877.450.7
201776.349
201668.952.6
201582.664.5
201486.354.9
20138559
201270.249.1
201175.855.3
201074.649.1
200968.947.8
20088355.3
200784.353.8
200664.344.3
200580.746.9
200474.744.6
20036338.9
20028356.4
200168.143.2
200074.745.9
199984.753.2
199886.964.4
199772.852.6
199668.443.7
19958050.4
19947445
199371.842.3
199268.938.5
19918051.4
19908559.3
198975.543.6
198879.960
198780.759.5
198689.570.2
19857647.9
198459.341.3
198383.653
19827854.4
198174.650.3
198069.749.9
197985.954.7
197873.843.1
197774.452.9
19767250
197573.149.7
197468.745.3
197381.561.5
197281.657.9
19719168.6
197075.246.4
196975.948.4
196881.650.6
19676137.8
196671.648
196577.652
196471.544.1
196377.851.5
196270.339
196175.643.8
19608147.9
195980.158.2
19586844.1
19577340.3
195686.251.4
195589.564
195484.571.1
195399.362.3
195291.254.1
195165.237.1

The month

August 2026 averaged 77.4°F in Monroe County, IL, the warmest August in the county average since 2021, tied 42nd warmest of 132 (with 2012) (county average from NOAA's monthly county data, 1895 to 2026).

The month in words
  • Tuesday 29 September 2026: a high of 81.5°F averaged over Monroe County, IL, the warmest 29 September in the county average since 2025, tied 25th warmest of 76 (with 1973) (county average from NOAA gridded data, 1951 to 2026).
  • Tuesday 29 September 2026: a low of 51.5°F averaged over Monroe County, IL, the warmest 29 September night in the county average since 2025, tied 34th warmest of 76 (with 1963) (county average from NOAA gridded data, 1951 to 2026).
Days of the month without a value
0

Nearby

St Louis, MO 34.4 mi, the nearest city with its own station