Sun Valley in Summer
In summer (June, July and August), Sun Valley sees average daytime highs around 83°F and overnight lows near 54°F, with 1.3 in of precipitation over about 9 wet days across the season. It is the warmest season of the year and the driest season of the year.
Over the season highs climb from about 73°F in early June to 83°F by late August. The sky is clear or mostly clear about 72% of the time across summer, and the air most often feels dry.
Summer is Sun Valley's best 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
- 83°F
- warmest season of the year
- Avg overnight low
- 54°F
- Precipitation
- 1.3 in
- 9 wet days
- Avg wind
- 5 mph
- Travel score
- 6.9
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Sun Valley in Summer
Over the season highs climb from about 73°F in early June to 83°F by late August.
A typical summer day in Sun Valley reaches about 83°F and drops to 54°F overnight. The warmest of the three months is July, the coolest June.
How summer really feels in Sun Valley
Once humidity and wind are folded in, summer brings about 0 days that feel above 90°F and 0 that feel at or below 32°F.
summer sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Sun Valley weather by month
How the three summer months (June, July and August) 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 Summer
The sky is clear or mostly clear about 72% of the time across summer.
Chance of precipitation in Summer
Sun Valley gets around 1.3 in of rain and snow over 9 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 5 mph across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 36 min in early June to 13 hours by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 8.0 kWh/m².
Is summer a good time to visit Sun Valley?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Sun Valley for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Sun Valley in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Sun Valley sees daytime highs around 83°F and nights near 54°F. Pack light clothes and sun protection. About 9 days see rain.
UV index in Sun Valley in Summer
Clear-sky midday UV across summer averages around 11 (very high — sun protection essential). 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 Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer 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.