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Weather extremes

How extreme does Aarau's weather get?

The hottest, coldest, wettest and snowiest days Aarau 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 Rheinfelden station 27 km away. Updated through February 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 Aarau has recorded — each shown against what a normal day that time of year looks like.

🔥 Hottest day
103°F Aug 13, 2003

That is about 24°F hotter than a normal August afternoon in Aarau (typical high near 79°F).

The three most extreme on record

1 103°F Aug 13, 2003
2 101°F Aug 5, 2003
3 101°F Jul 27, 2013
❄️ Coldest night
-9°F Jan 12, 1987

About 40°F colder than a normal January night in Aarau (typical low near 31°F).

The three most extreme on record

1 -9°F Jan 12, 1987
2 -5°F Jan 6, 1985
3 -3°F Jan 5, 1985
🌧️ Most rain in one day
2.96 in Dec 21, 1997

About 79% of a typical December's rain in a single day (Aarau averages roughly 3.7 in across the month).

The three most extreme on record

1 2.96 in Dec 21, 1997
2 2.83 in Jul 10, 1981
3 2.69 in Aug 8, 2007

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.

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

Aarau's record heat sits well above even a hot day for the season — August's 103°F is about 24°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, Aarau's warmest days reach the low 80s°F and its coldest nights drop to the low 30s°F. But across the record it has gone as high as 103°F and as low as −9°F. A single day has delivered over 3 inches of rain. 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 a national meteorological service, measured at Buchs / Aarau, about 3 km from the city centre.

How we build these numbers →