The best times to visit Sun Valley for ideal weather are

June 4th to September 23rd

based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.

 

 


Other Sun Valley Travel Info

Weather in Sun Valley

Temperature

Average temperatures in Sun Valley vary drastically. Considering humidity, temperatures feel cold for most of the year with a very low chance of rain or snow throughout the year. The area is somewhat temperate — in the 49th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Sun Valley, the hottest months are July, August, and then June. See average monthly temperatures below. The warmest time of year is generally mid July where highs are regularly around 85.9°F (29.9°C) with temperatures rarely dropping below 54.9°F (12.7°C) at night.

Sun Valley Temperatures (Fahrenheit)

Key
High
Average
Low

Sun Valley Temperatures (Celsius)

Key
High
Average
Low

“Feels-Like” Temperatures

The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.

Sun Valley Perceived Temperature (F)

Key
High
Average
Low

Sun Valley Perceived Temperature (C)

Key
High
Average
Low

 

Average Sun Valley Temperatures by Month

Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.

Show Fahrenheit

Month Avg. High (°F) Avg. Mean (°F) Avg. Low (°F)
Jan 30.8 21.9 14.9
Feb 35.3 26.9 20.1
Mar 45.4 35.3 27.3
Apr 54.5 42.6 32.4
May 64.2 51.8 40.1
Jun 74 60.2 46.4
Jul 85 69.7 54.8
Aug 82.3 67 53.2
Sep 74.1 58.7 46
Oct 58.7 45.7 36.3
Nov 43.1 33 26.1
Dec 30.9 23 16.7

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan -0.7 -5.6 -9.5
Feb 1.8 -2.8 -6.6
Mar 7.4 1.8 -2.6
Apr 12.5 5.9 0.2
May 17.9 11 4.5
Jun 23.3 15.7 8
Jul 29.4 20.9 12.7
Aug 27.9 19.4 11.8
Sep 23.4 14.8 7.8
Oct 14.8 7.6 2.4
Nov 6.2 0.6 -3.3
Dec -0.6 -5 -8.5

 


 

 

Humidity and Wind

Sun Valley has some humid months, and dry months in the opposite season. The least humid month is July (26.5% relative humidity), and the most humid month is December (69.3%).

Wind in Sun Valley is usually calm. The windiest month is August, followed by July and September. August’s average wind speed of around 7.1 knots (8.1 MPH or 13.1 KPH) is considered “a gentle breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in late April where average top sustained speeds reach 14.4 knots, which is considered a moderate breeze.

Relative Humidity (%)

The graph below shows the average % humidity by month in Sun Valley.

Key
Avg. Relative Humidity

Wind

The graph below shows wind speed (max and average) in knots.

Key
Max Sustained Wind
Average Daily Wind

Average Wind Speeds

Show Wind Speeds

All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.

Month Avg. Wind Avg. Wind Feel Sustained High Wind High Wind Feel
Jan 5 Light breeze 10.5 Gentle breeze
Feb 5.6 Light breeze 11.4 Significant breeze
Mar 6.3 Light breeze 12.9 Gentle breeze
Apr 6.9 Light breeze 14.2 Significant breeze
May 7 Gentle breeze 13.8 Gentle breeze
Jun 6.7 Light breeze 13.1 Significant breeze
Jul 7.1 Gentle breeze 13.3 Gentle breeze
Aug 7.1 Gentle breeze 12.9 Significant breeze
Sep 7 Gentle breeze 12.8 Gentle breeze
Oct 6.3 Light breeze 11.9 Significant breeze
Nov 5.7 Light breeze 11.3 Gentle breeze
Dec 5.3 Light breeze 10.9 Gentle breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 68%
Feb 63.4%
Mar 51.8%
Apr 38%
May 37.3%
Jun 35%
Jul 26.5%
Aug 29.2%
Sep 33.1%
Oct 47.2%
Nov 58.5%
Dec 69.3%

 

Is it Safe to Travel to Sun Valley?

Our best data indicates this area is generally safe. As of Dec 04, 2023 there are no travel advisories or warnings for the United States; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Dec 04, 2023.


 

The Busiest and Least Crowded Months

The busiest month for tourism in Sun Valley, ID, US is July, followed by June and August. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Sun Valley in December. Those willing to visit at these times will likely find it the least expensive month.

Estimated Tourism by Month

 

Most Popular Months to Visit

Key
Tourists Seeking Accommodations

Tourism graph is based on Google searches for services used by tourists relative to the rest of the year. Tourism data for this area is extrapolated based on nearby areas. Displayed data is calculated relative to the peak, so a score of 36.5 in December means 36.5% of the tourists vs. July.

 

 

Overall Sun Valley Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderately cold. Highs range from 69.1°F (20.6°C) and 37.1°F (2.8°C) with warmer temperatures in the later months. Spring is the second busiest for tourism, which makes it a good time for those looking for things to do.

Summer (June through August)

The middle-year months have very comfortable weather with high temperatures that are comfortable. June – August is the busiest season for tourism in Sun Valley, so lodging and other accommodations may cost more than usual.

Fall (September through November)

Fall daily highs range from 76.4°F (24.7°C) and 37.9°F (3.3°C), which will feel chilly given the humidity and wind. Tourism is fairly slow during these months due to the weather, so hotels may be lower priced.

Winter (December through February)

Weather is far too cold this time of year in Sun Valley to be enjoyable for warm weather travelers. The average high during this season is between 37.4°F (3°C) and 27.2°F (-2.7°C). These times of year are the slowest with tourists.

 

Best Times to Travel› the United States › Sun Valley, ID, US