Macoupin County Climate
Macoupin County, Illinois
Avg Annual Temp
54.1°F
Annual Precip
39.4"
Annual Snowfall
16.4"
Extreme Heat Days
25.799999999999997
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Macoupin County Weather
Warmer and Wetter than Average
Macoupin County's 54.1°F average temperature makes it warmer than the national median. It receives 39.4 inches of rain annually, placing it in the heart of the humid continental zone.
Leaning Toward Illinois' Warmer Side
The county's 54.1°F annual average is over a degree higher than the Illinois state average of 52.8°F. This warming trend is evident in its mild 31.3°F winter average.
Transitioning Toward Southern Illinois
Macoupin acts as a bridge, with 26 extreme heat days—fewer than southern Marion but more than northern Livingston. Its 16.4 inches of snowfall is also a midpoint for the state.
Hot Summers and Soft Winters
July averages a warm 76.7°F, contributing to 26 days per year that exceed 90°F. Winters are relatively mild, with January temperatures averaging 28.1°F.
Manage Humidity and Mid-Range Heat
Residents should prepare for high summer humidity and nearly a month's worth of 90°F days. With 16.4 inches of snow, standard winter gear is necessary but rarely faces northern-style blizzards.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.