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.
Sun Valley Travel Guide
Other Sun Valley Travel Info
Weather in Sun Valley
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)
Sun Valley Temperatures (Celsius)
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)
Sun Valley Perceived Temperature (C)
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.
|Month||Avg. High (°F)||Avg. Mean (°F)||Avg. Low (°F)|
|Month||Avg. High (°C)||Avg. Mean (°C)||Avg. Low (°C)|
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.
The graph below shows wind speed (max and average) in knots.
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|
Is it Safe to Travel to Sun Valley?
Our best data indicates this area is generally safe. As of Oct 07, 2019 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 Sep 23, 2019.
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
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.