Glen Carbon, IL Weather & Climate Normals
What a normal year in Glen Carbon actually looks like
On the 30-year record NOAA keeps for Glen Carbon, IL, the comfort score comes out to 49/100, strongly seasonal: Comfortable weather is limited to a shorter window; summers, winters, or precipitation swing wide. Only 5 months a year land in the 55–75°F range this site treats as mild.
How much Glen Carbon's weather actually swings
Average temperatures in Glen Carbon run from 30°F in Jan up to 78°F in Jul, a 47.9°F seasonal swing, one of the widest gaps in this dataset.
How wet Glen Carbon actually gets
Glen Carbon averages 41.87in of precipitation a year across roughly 99 days with measurable rain or snow; the nearest NOAA station does not record snowfall, so no snow figure is shown rather than guessed.
Glen Carbon against the rest of the country
Out of 4876 cities scored here, Glen Carbon comes in at 2158; within IL alone it ranks 18 of 330. Population is about 13,883.
Checking the actual forecast
These figures come from ALTON - MELVIN PRICE L&D, IL US, the NOAA station 11.7 miles from Glen Carbon, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why some cities show no snow or rain figure · What a 30-year climate normal actually is