The month in detail
What to expect in September
Off-season for skiing Sun Valley — lifts are closed. Consider hiking, mountain biking or summer activities at altitude. Rain risk remains low (15% of days), leaving good room for outdoor activities.
September ranks 4 out of 12 months in Sun Valley. Compared to August: −6°C daytime, −1.2h of sun per day.
This month's conditions
What it's like in September
UV index
6 · high
sunscreen and hat advised
Feels like
dry air
1°
Daylight
12.3h of daylight
Air quality
good
AQI 34
Compare
Is September the right month?
The best month in Sun Valley is July (9.3/10), 1.3 pt higher than September.
Book
Plan your trip
Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.
Stay
Hotels & rentals · Sun Valley
Expedia →
Activities
Tours, tickets, experiences
See ↓
Flights
Multi-airline comparator
Kiwi →
🎟️ Activities & tours · Sun Valley
GetYourGuide selection · free cancellation
Practical info
What you need to know before you go
Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a mountain stay.
Country · United States
🗣️LanguageEnglish
💶CurrencyUS Dollar ($)
🚗DrivingRight-hand
🛡️Safety ⓘVery safe · 1/5
💰Cost of living ⓘExpensive · 4/5
🌡️ Climate
🌍Climate typeAlpine mountain climate
📈Climate trend ⓘStable
🔥Hottest monthJuly · 28°C
❄️Coolest monthJanuary · 0°C
🌧️Rainiest month ⓘFebruary · 27%
🏔️ Mountain stay
⛰️Village altitude1753 m
🎿Ski area1753 → 2789 m
⛷️Ski seasonDec → May
🥾Hiking seasonJun → Sep
🧗High mountains ⓘGuide recommended
Explore
Other destinations in September
If September doesn't convince you for this destination, compare with others.
Similar climate
Park CityUnited StatesSteamboat SpringsUnited StatesAspenUnited StatesJackson HoleUnited StatesLake TahoeUnited States
Location
Where is Sun Valley ?
Global position + regional geographic context.
🌍 World
🔍 Geographic context
United StatesAlpine mountain climate climate with a 9.3 → 4.0 gap between best and worst month. 10 years of ERA5 data to choose by project.
43.70°N · 114.35°W
Questions
Frequently asked questions
When is the best time to visit Sun Valley?
It depends on the activity. For skiing: March (ski score 8.3/10). For hiking/summer: June (8.8/10, 21.0°C).
Can you ski in Sun Valley in winter?
Yes, it's peak ski season. Average ski score December–February: 7.8/10. Cold temperatures (0°C max in January) and frequent snowfall.
Is it warm in Sun Valley in summer?
In June, temperatures average 21.0°C. Best period for hiking and outdoor activities.
What is the wettest month in Sun Valley?
April is the wettest month with April has the lowest climate score of the year.
Do you need sun protection in Sun Valley in September?
The average UV index reaches 6 in September in Sun Valley (high), with about 12.3h of daylight. Sunscreen and hat advised.