Illinois · county areal climate 1951–2025

Mason County, IL

A 37.5" / 53.1°F normal · 2025 ran 71% of normal precipitation.
2026 so far · through Jul 25: This area is at 116% (26.33") of the 1996–2025 to-date normal — the 16th wettest start of 76 years. Temperature +1.9°F vs normal. U.S. year-to-date →

Normal (1996–2025)

37.5in
annual precipitation · 53.1°F

2025 vs Normal

71%
26.6" · 53.8°F (+0.7 vs normal)

Wettest Year

57.4in
2009

Driest Year

22.6in
1988

Biggest Rain Day

3.57in
Dec 3 · 1982

Warmest Year

55.7°F
2012

Record

1951–2025
75 complete years · NOAA nClimGrid

Monthly Climate

26°
J
31°
F
42°
M
53°
A
64°
M
73°
J
76°
J
74°
A
68°
S
55°
O
43°
N
32°
D
—— normal temperature (°F) · ▮ normal precipitation (in) · 1996–2025
Areal nClimGrid averages (NOAA/NCEI) over the whole area — an average across the region, not a single station. Separate from the station records.

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