Sun Valley in Winter
In winter (December, January and February), Sun Valley sees average daytime highs around 41°F and overnight lows near 23°F, with 7.5 in of precipitation over about 24 wet days across the season. It is the coldest season of the year and the wettest season of the year.
Across winter, daytime highs hold fairly steady around 41°F. The sky is clear or mostly clear about 32% of the time across winter, and the air most often feels dry.
Winter is Sun Valley's weakest season of the year to visit on our travel score. For the whole year in context, see Sun Valley's year-round climate.
- Avg daytime high
- 41°F
- coldest season of the year
- Avg overnight low
- 23°F
- Precipitation
- 7.5 in
- 24 wet days
- Avg wind
- 4 mph
- Travel score
- 0.2
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Sun Valley in Winter
Across winter, daytime highs hold fairly steady around 41°F.
A typical winter day in Sun Valley reaches about 41°F and drops to 23°F overnight. The warmest of the three months is February, the coolest December.
How winter really feels in Sun Valley
Once humidity and wind are folded in, winter brings about 0 days that feel above 90°F and 90 that feel at or below 32°F.
The story in winter is cold — wind chill drags the overnight "feels like" below the raw low.
Sun Valley weather by month
How the three winter months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 40° / 22° | 2.6 | 8 | 6.8 | 9.5 | 0.0 |
| Feb | 43° / 24° | 2.3 | 8.5 | 7.3 | 10.4 | 0.6 |
| Mar | 50° / 28° | 2.2 | 8 | 6 | 11.7 | 2.4 |
| Apr | 57° / 34° | 1.3 | 6.9 | 3.6 | 13 | 4.4 |
| May | 67° / 42° | 1.2 | 6.8 | 1.2 | 14.1 | 6.8 |
| Jun | 78° / 50° | 0.6 | 3.5 | 0.2 | 14.7 | 8.1 |
| Jul | 87° / 56° | 0.4 | 2.8 | 0 | 14.5 | 6.1 |
| Aug | 85° / 56° | 0.3 | 2.7 | 0 | 13.6 | 6.6 |
| Sep | 77° / 50° | 0.4 | 2.5 | 0 | 12.3 | 8.6 |
| Oct | 64° / 40° | 0.9 | 3.5 | 0.8 | 10.9 | 7.0 |
| Nov | 50° / 29° | 1.4 | 5.7 | 3.6 | 9.8 | 2.6 |
| Dec | 39° / 21° | 2.5 | 7.6 | 6.6 | 9.3 | 0.1 |
Cloud cover in Winter
The sky is clear or mostly clear about 32% of the time across winter.
Chance of precipitation in Winter
Sun Valley gets around 7.5 in of rain and snow over 24 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 4 mph across winter.
Sunrise & sunset in Winter
Daylight runs from about 9 h 24 min in early December to 11 hours by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 3.0 kWh/m².
Is winter a good time to visit Sun Valley?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a weaker month for outdoor sightseeing in Sun Valley.
What to pack for Sun Valley in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Sun Valley sees daytime highs around 41°F and nights near 23°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 24 days see rain.
UV index in Sun Valley in Winter
Clear-sky midday UV across winter averages around 3 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Sun Valley peaks around June 22 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 23 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 4 | 5 | 7 | 9 | 11 | 11 | 10 | 7 | 5 | 2 | 2 |
| Level | Moderate | Moderate | Moderate | High | Very high | Extreme | Extreme | Very high | High | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 4 | Moderate |
| Mar | 5 | Moderate |
| Apr | 7 | High |
| May | 9 | Very high |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 10 | Very high |
| Sep | 7 | High |
| Oct | 5 | High |
| Nov | 2 | Moderate |
| Dec | 2 | Moderate |
Air quality in Sun Valley in Winter
Average fine-particle pollution (PM2.5) through the year — so you can see where winter falls, not just the annual average.
Air quality in Sun Valley is worst in July — around 51 µg/m³ PM2.5 (poor), about 8.5× the cleanest month (December, 6 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 7 | 8 | 10 | 10 | 10 | 10 | 51 | 42 | 45 | 15 | 7 | 6 |
| Level | Good | Good | Good | Good | Good | Good | Poor | Poor | Poor | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 7 | Good |
| Feb | 8 | Good |
| Mar | 10 | Good |
| Apr | 10 | Good |
| May | 10 | Good |
| Jun | 10 | Good |
| Jul | 51 | Poor |
| Aug | 42 | Poor |
| Sep | 45 | Poor |
| Oct | 15 | Moderate |
| Nov | 7 | Good |
| Dec | 6 | Good |
Where is Sun Valley?
Sun Valley sits at 39.6°N, 119.8°W, 4,724 ft above sea level, in United States. The nearest listed city is Sparks, 4.3 mi away.
Topography around Sun Valley
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Sun Valley.
Within 2 miles, the terrain around Sun Valley has significant variations in elevation — a maximum elevation change of 1,112 ft around an average of 4,898 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,911 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 7,779 ft.
The land around Sun Valley is covered by grassland (51%) and artificial surfaces (31%) within 2 miles, grassland (55%) and artificial surfaces (22%) within 10 miles, and grassland (40%) and trees (29%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sun Valley (39.5963°, -119.776°, elevation 4,724 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.