How extreme does Sun Valley's weather get?

The hottest, coldest, wettest and snowiest days Sun Valley 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 (1973–present), from the Ketchum Rs 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 Sun Valley has recorded — each shown against what a normal day that time of year looks like.

🔥 Hottest day

98°F Jul 13, 2002

That is about 17°F hotter than a normal July afternoon in Sun Valley (typical high near 81°F).

The three most extreme on record

1 98°F Jul 13, 2002

2 97°F Jun 17, 1974

3 97°F Jul 4, 2001

❄️ Coldest night

-37°F Dec 22, 1990

About 46°F colder than a normal December night in Sun Valley (typical low near 9°F).

The three most extreme on record

1 -37°F Dec 22, 1990

2 -36°F Dec 23, 1990

3 -33°F Dec 23, 1983

🌧️ Most rain in one day

2.76 in Mar 11, 1995

More rain in a single day than Sun Valley usually gets in the whole month of March (typical March total about 1.8 in).

The three most extreme on record

1 2.76 in Mar 11, 1995

2 1.88 in Dec 13, 1995

3 1.85 in Feb 28, 2006

⛄ Most snow in one day

24.0 in Dec 12, 2022

About 81% of a typical December's snow in a single day (Sun Valley averages roughly 30 in across the month).

The three most extreme on record

1 24.0 in Dec 12, 2022recent

2 22.0 in Feb 17, 1990

3 22.0 in Jan 28, 2021

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.

normal range of daily temperatureshottest ever recordedcoldest ever recorded

Sun Valley's record heat sits well above even a hot day for the season — July's 98°F is about 17°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, Sun Valley's warmest days reach the low 80s°F and its coldest nights drop to the high 0s°F. But across the record it has gone as high as 98°F and as low as −37°F. A single day has delivered over 3 inches of rain or close to 24 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 — 1991–2020 normals computed from 29 years of daily observations at Ketchum RS, a weather station, about 2 km from the city centre. The underlying daily records come from NOAA's global station network.

How we build these numbers →

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