Climateby Month

Sun Valley, ID climate by month

NOAA 1991-2020 normals · 5,952 ft elevation

Summers in Sun Valley are warm; winters are cold and snowy. Highs peak at 80°F in July and fall to 30°F in December. The wettest month is December (about 11 wet days) and the driest is August (about 4). Normal snowfall is about 102 in a year. The most comfortable time to visit is June.

Warmest month
80°F
July normal high
Coldest month
8°F
January normal low
Wet days a year
84
17.3 in of precipitation
Snow a year
102.0 in
normal snowfall

How warm is Sun Valley?

Normal highs range from 30°F in December to 80°F in July.

0°20°40°60°80° January: normal high 31°F (-1°C), low 8°F (-13°C) February: normal high 35°F (2°C), low 11°F (-12°C) March: normal high 43°F (6°C), low 19°F (-7°C) April: normal high 52°F (11°C), low 27°F (-3°C) May: normal high 62°F (17°C), low 35°F (2°C) June: normal high 70°F (21°C), low 40°F (4°C) July: normal high 80°F (27°C), low 45°F (7°C) 80° 45° August: normal high 79°F (26°C), low 44°F (7°C) September: normal high 69°F (21°C), low 36°F (2°C) October: normal high 56°F (13°C), low 28°F (-2°C) November: normal high 41°F (5°C), low 17°F (-8°C) December: normal high 30°F (-1°C), low 9°F (-13°C) 30° 9° JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Sun Valley?

December has the most wet days (about 11); the year brings about 17 in of precipitation.

January: 10 wet days February: 9 wet days March: 8 wet days April: 7 wet days May: 8 wet days June: 8 wet days July: 4 wet days August: 4 wet days 4 September: 4 wet days October: 5 wet days November: 6 wet days December: 11 wet days 11 JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 102.0 in a year, most of it in December.

January: 27.0 in of snow February: 17.2 in of snow March: 10.5 in of snow April: 3.2 in of snow May: 0.2 in of snow June: 0.0 in of snow 0.0 July: 0.0 in of snow August: 0.0 in of snow September: 0.0 in of snow October: 1.6 in of snow November: 10.3 in of snow December: 32.0 in of snow 32.0 JFMAMJJASOND

How humid is Sun Valley?

Muggy days (dew point 65°F or higher) are rare in any month.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 0 muggy days July: 0 muggy days August: 0 muggy days September: 0 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Stanley Ranger Station, 44 mi NW of the city center (the nearest airport with complete hourly records).

How much daylight?

Daylight ranges from about 9.0 hours in December to 15.4 hours in June.

January: 9.4 hours of daylight February: 10.5 hours of daylight March: 11.9 hours of daylight April: 13.4 hours of daylight May: 14.7 hours of daylight June: 15.4 hours of daylight 15.4 July: 15.1 hours of daylight August: 13.9 hours of daylight September: 12.5 hours of daylight October: 11.0 hours of daylight November: 9.7 hours of daylight December: 9.0 hours of daylight 9.0 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Sun Valley, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 31°F8°F 2.3 in10 27.0 in 0 9.4 h
February 35°F11°F 1.9 in9 17.2 in 0 10.5 h
March 43°F19°F 1.8 in8 10.5 in 0 11.9 h
April 52°F27°F 1.2 in7 3.2 in 0 13.4 h
May 62°F35°F 1.8 in8 0.2 in 0 14.7 h
June 70°F40°F 1.3 in8 0.0 in 0 15.4 h
July 80°F45°F 0.6 in4 0.0 in 0 15.1 h
August 79°F44°F 0.5 in4 0.0 in 0 13.9 h
September 69°F36°F 1.0 in4 0.0 in 0 12.5 h
October 56°F28°F 1.4 in5 1.6 in 0 11.0 h
November 41°F17°F 1.2 in6 10.3 in 0 9.7 h
December 30°F9°F 2.6 in11 32.0 in 0 9.0 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Sun Valley

By our comfort score, the best month is June.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 230628
Feb 300521
Mar 420511
Apr 56342
Jun 821940
Jul 741322
Aug 761621
Sep 782020
Oct 54632
Nov 341415
Dec 210728

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Sun Valley

The last spring frost typically comes around May 13, and the first fall frost around Oct 2, leaving 139 frost-free days in a typical year.

Frost and freeze dates for Sun Valley
Typical date1 year in 10
Last spring frost (32°F)May 13after Jun 3
First fall frost (32°F)Oct 2before Sep 15
Last hard freeze (28°F)Apr 28after May 11
First hard freeze (28°F)Oct 14before Sep 30
Frost-free season139 daysunder 112 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Bellevue (USC00100774), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Idaho.

Hottest and coldest readings, 1991-2020

The highest reading was 98°F (July 13, 2002); the lowest was -22°F (February 4, 1996, and 1 other day).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Sun Valley

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain and snowfall: Ketchum RS (USC00104845), 1.0 mi SSW of the city center, 5,890 ft (62 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Frost dates: Bellevue (USC00100774), 17 mi SSE of the city center, 5,192 ft (760 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Stanley Ranger Station (726824-04112), 44 mi NW of the city center, 6,495 ft (543 ft higher than the city). Hourly observations, 1991-2020.
  • Not available for this location: snow depth, humidity and wind by hour and cloud cover (no station close enough or similar enough in elevation).

Distances from the city center (USGS). Methodology · Report an error