Sun Valley, ID weather in December
December in Sun Valley: cold and snowy. Highs 30°F, lows 9°F, about 11 wet days and about 32.0 in of snow. This is the depth of winter in Sun Valley. Pack for serious cold.
- Normal high
- 30°F
- Normal low
- 9°F
- Wet days
- 11
- 2.6 in total
- Snowfall
- 32.0 in
- normal snowfall
How December changes from start to finish
| December 1 | December 31 | |
|---|---|---|
| Normal high | 34°F | 30°F |
| Normal low | 12°F | 8°F |
| Chance of a wet day | 31% | 34% |
| Sunrise / sunset | 7:51 am / 5:01 pm | 8:11 am / 5:09 pm |
| Daylight | 9.2 h | 9.0 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Mountain Time).
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F0 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow11 of 31
- Notable rainat least 0.10 in7 of 31
- Freezing nightslow 32°F or below31 of 31
Average days per December, counted from daily records for each year 1991-2020.
Rain and snow in December
Normal precipitation is 2.6 in; a dry December brings about 1.1 in and a wet one about 3.5 in (25th and 75th percentiles). About 2 days bring half an inch or more. Normal snowfall is 32.0 in, with about 8 days of an inch or more.
How December varies from year to year
- Warmest December, 1991-20201999: average high 38°F
- Coolest December2016: average high 25°F
- Wettest December1996: 7.0 in
- Driest December2013: 0.6 in
- Highest reading59°F (December 1, 2008)
- Lowest reading-16°F (December 22, 1998)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
December compared with November and January
| November | December | January | |
|---|---|---|---|
| Normal high | 41°F | 30°F | 31°F |
| Normal low | 17°F | 9°F | 8°F |
| Wet days | 6 | 11 | 10 |
| Comfortable days | 1 | 0 | 0 |
| Daylight | 9.7 h | 9.0 h | 9.4 h |
Highs change by -11°F from November and +1°F into January.
Nearby alternatives in December
- Warmer: Boise, ID93 mi · high 39°F · 12 wet days
- Cooler: West Yellowstone, MT174 mi · high 23°F · 15 wet days
How Sun Valley ranks in December
- Normal high362nd warmest of 378 cities; 2nd of 2 in Idaho
- Wet days266th driest of 378
- Comfortable days301st most of 340
What to pack for Sun Valley in December
- A warm jacket – lows near 9°F, highs near 30°F
- A rain jacket or umbrella – rain or snow on about 11 days
- Waterproof boots – about 32.0 in of snow in a typical year
- A hat and gloves – about 31 freezing nights
Heating and cooling
December has 1403 heating degree days and 0 cooling degree days (base 65°F), 15% of the year's total heating and cooling demand.
Questions
How cold is Sun Valley in December?
The normal high is 30°F and the normal low is 9°F. From 1991 to 2020 the coldest December reading was -16°F (December 22, 1998).
Does it rain a lot in Sun Valley in December?
About 11 days in December have at least 0.01 in of precipitation, and the normal total is 2.6 in. The wettest December in 1991-2020 was in 1996 (7.0 in); the driest was in 2013 (0.6 in).
Does it snow in Sun Valley in December?
Yes. Normal snowfall in December is 32.0 in.
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).