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Weather extremes

How extreme does DeKalb's weather get?

The hottest, coldest, wettest and snowiest days DeKalb has recorded — the outer limits of what its weather can do, and how far they sit beyond a normal day.

Based on 50+ years of daily weather observations (1971–present), from the De Kalb station 2 km away. Updated through May 2026 — an all-time extreme only changes when a more extreme day actually occurs, so some dates are old. That is normal, not stale data.

The four kinds of extreme

The hottest, coldest, wettest and snowiest single days DeKalb has recorded — each shown against what a normal day that time of year looks like.

🔥 Hottest day
103°F Aug 17, 1988

That is about 22°F hotter than a normal August afternoon in DeKalb (typical high near 81°F).

The three most extreme on record

1 103°F Aug 17, 1988
2 102°F Aug 18, 1988
3 102°F Jul 14, 1995
❄️ Coldest night
-27°F Jan 20, 1985

About 40°F colder than a normal January night in DeKalb (typical low near 13°F).

The three most extreme on record

1 -27°F Jan 20, 1985
2 -26°F Jan 30, 2019
3 -26°F Jan 31, 2019
🌧️ Most rain in one day
8.09 in Jul 18, 1996

More rain in a single day than DeKalb usually gets in the whole month of July (typical July total about 4.0 in).

The three most extreme on record

1 8.09 in Jul 18, 1996
2 6.26 in Jul 22, 1982
3 5.71 in Aug 14, 1987
Most snow in one day
15.7 in Feb 2, 2011

Close to a whole typical February's snow in one day (DeKalb averages about 9 in across the month).

The three most extreme on record

1 15.7 in Feb 2, 2011
2 15.6 in Jan 13, 1979
3 10.6 in Dec 15, 1987

How hot and cold it gets, month by month

The shaded band is the normal range of daily temperatures for each month. The dots show the most extreme it has ever been — so you can see how far beyond a normal day the records really sit.

-50°-30°-10°10°30°50°70°90°110°130° all-time high 103°F JanFebMarAprMayJunJulAugSepOctNovDec
normal range of daily temperatureshottest ever recordedcoldest ever recorded

DeKalb's record heat sits well above even a hot day for the season — August's 103°F is about 22°F beyond a normal hot afternoon. Its record cold is just as far below a normal winter night — the dots mark how rare each extreme really is.

In plain terms

In a normal year, DeKalb's warmest days reach the low 80s°F and its coldest nights drop to the low 10s°F. But across the record it has gone as high as 103°F and as low as −27°F. A single day has delivered over 8 inches of rain or close to 16 inches of snow. Those are the outer edges worth knowing if you are moving here, planning a trip, or thinking about a house.
Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Aurora Water (NOAA GHCN station USC00110338), about 40 km from the city centre.

How we build these numbers →