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Union County, IL

: September 2026 so far averaged 77.4°F in Union 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
81.3°F
Warmest since 2025
25th warmest of 76
Low
50.6°F
Warmest since 2025
36th warmest of 76

No measurable precipitation in the county average of Union County, IL for 17 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).

Every 29 September high of the county average in Union County, IL since 1951: 81.3°F in 2026; the highest is 97.6°F, in 1953.
2025: 84.1°F1953: 97.6°F2026: 81.3°F 2026 81.3°F 1953 97.6°F since 2025 1951 2026
  • Normal range, 67.8 to 84.5°F
Every year as a table

Every 29 September low of the county average in Union County, IL since 1951: 50.6°F in 2026; the lowest is 37.2°F, in 1951.

YearHigh, °FLow, °F
202681.350.6
202584.155.9
202468.564
202384.164.2
202267.841.3
202186.460
202067.846
201988.567
201875.349.9
201778.450.3
201671.450.8
201578.762.7
20148455.2
201381.461.1
20127249.7
201176.752.3
201075.546.1
200972.747
200884.152.8
200783.952
200665.942.8
200581.147
200477.746
200364.440
200281.856.8
200167.844.4
200076.146
199989.252.4
199890.662.4
199779.551.4
199668.842.7
199579.747.9
199475.543.7
199372.642.6
199272.440.3
19917947.7
199084.757.3
198971.845.4
198877.558.7
198783.859.4
198691.168.6
19857245.6
198460.841.9
198383.650.2
198278.351
198175.246.7
198071.351
197982.558
197872.644.5
197772.751.3
197670.451.9
197570.744.6
197471.346.8
197381.565.8
197280.360.5
197188.665.2
19707544.1
196977.544.7
196880.549.2
196759.137.3
196673.546.9
19657851.5
19646749
196376.751.2
196269.237.9
196176.844
196082.449.3
19598161.1
195868.345.2
195772.943.2
195685.245.2
195589.562.1
195483.968
195397.653.5
195288.351.5
19516737.2

The month

August 2026 averaged 76.9°F in Union County, IL, the warmest August in the county average since 2024, tied 39th warmest of 132 (with 1998, 1926 and 1895) (county average from NOAA's monthly county data, 1895 to 2026).

The month in words
  • Tuesday 29 September 2026: a high of 81.3°F averaged over Union County, IL, the warmest 29 September in the county average since 2025, 25th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
  • Tuesday 29 September 2026: a low of 50.6°F averaged over Union County, IL, the warmest 29 September night in the county average since 2025, 36th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
Days of the month without a value
0

Nearby

Carbondale, IL 20.6 mi, the nearest city with its own station