Sun Valley, United States experiences average highs of 18°C (64°F) and lows of 6°C (43°F) throughout the year. The climate is relatively dry, with only 6 rainy days per month on average. Sunshine is abundant, averaging about 11 hours per day. Average highs have warmed by 0.6°C (1.1°F) across the available records.
Sun Valley, United States Weather & Climate 2026
Monthly climate averages for Sun Valley, United States. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Apr–Oct 
Wetter season: Jan–Dec At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
6.1/10
Best: June, July, August, September, October
UV Index
6
High
Temperature 18°C / 6°C
Feels Like 15°C / 4°C
Rainy Days 6
Rainfall 40 mm
Sunshine 11 h
Humidity 53%
Wind Speed 13 km/h
Dew Point 2°C
Snow Days 6 days
Frost Days 12 days
Hottest Month
33°C
July
Avg Low18°C
Rain3days
Coldest Month
-3°C
January
Avg High5°C
Rain9days
Driest Month
3days
June
Avg High29°C
Avg Low14°C
Windiest Month
16 km/h
June (Gusts 48)
Worst Time to Visit
Consider avoiding January, February, March, December due to very cold temperatures.
Sun Position
Sunrise 05:32
Daylight 15h
Sunset 20:30
Live conditions—
Sun Valley on the map · live conditions
Sun Valley, United States
- Continent
- Americas
- Country
- United States
- City
- Sun Valley
- Population
- 19.3K
- Elevation
- 1,440 m
- Coordinates
- 39.60°, -119.78°
Seasonal Breakdown
Spring
Mar–May
Avg High 16°C
Avg Low 4°C
Rain 7 days/mo
Summer
Jun–Aug
Avg High 31°C
Avg Low 17°C
Rain 3 days/mo
3/3 best months
Autumn
Sep–Nov
Avg High 19°C
Avg Low 8°C
Rain 4 days/mo
2/3 best months
Winter
Dec–Feb
Avg High 6°C
Avg Low -3°C
Rain 8 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 5°C / -3°C . Feb: 6°C / -3°C . Mar: 9°C / 0°C . Apr: 16°C / 4°C . May: 21°C / 9°C . Jun: 29°C / 14°C . Jul: 33°C / 18°C . Aug: 32°C / 18°C . Sep: 27°C / 14°C . Oct: 19°C / 8°C . Nov: 11°C / 2°C . Dec: 6°C / -2°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 83 mm. Feb: 71 mm. Mar: 73 mm. Apr: 28 mm. May: 33 mm. Jun: 10 mm. Jul: 8 mm. Aug: 13 mm. Sep: 13 mm. Oct: 33 mm. Nov: 36 mm. Dec: 78 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 77%. Feb: 69%. Mar: 68%. Apr: 57%. May: 47%. Jun: 34%. Jul: 28%. Aug: 32%. Sep: 37%. Oct: 46%. Nov: 63%. Dec: 76%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 10 km/h . Feb: 12 km/h . Mar: 14 km/h . Apr: 16 km/h . May: 16 km/h . Jun: 16 km/h . Jul: 15 km/h . Aug: 14 km/h . Sep: 13 km/h . Oct: 12 km/h . Nov: 11 km/h . Dec: 10 km/h .
Sunshine
Sunshine
Sunshine: Jan: 7h. Feb: 9h. Mar: 10h. Apr: 12h. May: 13h. Jun: 14h. Jul: 14h. Aug: 13h. Sep: 11h. Oct: 10h. Nov: 8h. Dec: 7h.
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 3. Feb: UV 4. Mar: UV 6. Apr: UV 7. May: UV 8. Jun: UV 8. Jul: UV 9. Aug: UV 8. Sep: UV 7. Oct: UV 5. Nov: UV 4. Dec: UV 3.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 9 days. Feb: 9 days. Mar: 11 days. Apr: 4 days. May: 2 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 1 days. Nov: 4 days. Dec: 8 days.
Climate Trends
Average highs have warmed by 0.6°C (1.1°F) across the available records. Average rainfall has remained broadly steady.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 32°C | Jul · 33°C |
| Coldest month | Jan 2025 · -3°C | Jan · -3°C |
| Wettest month | Feb 2025 · 126 mm | Jan · 83 mm |
| Windiest month | May 2025 · 16 km/h | Jun · 16 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Poor April
Fair May
Good June best
Excellent July best
Excellent August best
Excellent September best
Excellent October best
Excellent November
Fair December
Poor | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 5°C / -3°C | 2°C / -7°C | 9days (83 mm) Wet | 7.4h Good | 77% Humid | 3.1 Moderate | Poor | View Details |
| February | 6°C / -3°C | 3°C / -6°C | 8days (71 mm) Wet | 8.9h Good | 69% Muggy | 4.3 Moderate | Poor | View Details |
| March | 9°C / 0°C | 6°C / -4°C | 10days (73 mm) Wet | 9.9h Good | 68% Muggy | 5.7 High | Poor | View Details |
| April | 16°C / 4°C | 13°C / 1°C | 5days (28 mm) Good | 11.6h Excellent | 57% Moderate | 7.1 Very High | Fair | View Details |
| May | 21°C / 9°C | 19°C / 6°C | 7days (33 mm) Good | 12.7h Excellent | 47% Moderate | 8 Very High | Good | View Details |
| June best | 29°C / 14°C | 26°C / 12°C | 3days (10 mm) Excellent | 13.6h Excellent | 34% Comfortable | 8.4 Very High | Excellent | View Details |
| July best | 33°C / 18°C | 32°C / 17°C | 3days (8 mm) Excellent | 13.5h Excellent | 28% Comfortable | 8.5 Very High | Excellent | View Details |
| August best | 32°C / 18°C | 30°C / 17°C | 4days (13 mm) Good | 12.5h Excellent | 32% Comfortable | 7.8 Very High | Excellent | View Details |
| September best | 27°C / 14°C | 24°C / 13°C | 3days (13 mm) Excellent | 11.3h Excellent | 37% Comfortable | 6.6 High | Excellent | View Details |
| October best | 19°C / 8°C | 16°C / 5°C | 3days (33 mm) Excellent | 9.7h Good | 46% Moderate | 5 Moderate | Excellent | View Details |
| November | 11°C / 2°C | 8°C / -1°C | 6days (36 mm) Good | 8.4h Good | 63% Muggy | 3.5 Moderate | Fair | View Details |
| December | 6°C / -2°C | 3°C / -6°C | 8days (78 mm) Wet | 7.1h Good | 76% Humid | 2.7 Moderate | Poor | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Sun Valley are June, July, August, September, October, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Sun Valley, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Sun Valley is July, with average daytime highs of 33°C (92°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Sun Valley is January, with average overnight lows of -3°C (26°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Sun Valley is January, averaging 83mm of precipitation across 9 rainy days. An umbrella or waterproof jacket is essential.
Sun Valley receives approximately 127 sunshine hours per year. The sunniest month is June with around 14 hours. Based on climate data for Sun Valley.
The least favorable months to visit Sun Valley are January, February, March, December, primarily due to very cold temperatures. For the best conditions, consider June, July, August, September, October instead.
The annual average UV index in Sun Valley is 6, classified as high. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Sun Valley is 53%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes, Sun Valley receives snow. Months with snowfall average 6 snow days and 20 cm (8 in) of accumulation, with about 12 frost days during winter.
Average wind speeds in Sun Valley are 13 km/h (8 mph). The windiest month is June with peak winds reaching 16 km/h (10 mph) (gusts up to 48 km/h / 30 mph).
Sun Valley averages 11 clear-sky days per month with overall cloud cover around 39%. The clearest skies occur in July.
The annual average dew point in Sun Valley is 2°C (36°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Sun Valley has a Hot-Summer Mediterranean climate, classified as Csa under the Köppen system. Temperate climates have mild winters and warm summers, with rainfall spread across the year and four distinct seasons.
The 'feels like' temperature in Sun Valley ranges from 4°C (39°F) to 15°C (59°F) on average. The 'feels like' temperature closely matches the actual temperature throughout most of the year.
Yes, June is a great time to visit Sun Valley. It earns a climate score of 9.5/10 with Excellent.
For June in Sun Valley, pack Breathable clothing, Sunscreen (SPF 30+), Sun hat, Sunglasses, Sandals. With average highs of 29°C (83°F) and 3 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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