Home › Cities › United States › Idaho › Sun Valley

Sun Valley, Idaho climate

Dsb Mediterranean-influenced warm-summer humid continental

Sun Valley has a seasonal cold-temperate climate (Mediterranean-influenced warm-summer humid continental, Köppen Dsb). The hottest month is July with an average daily high near 27°C, while the coldest is January averaging around −14°C at night. Precipitation totals about 429 mm a year and is strongly seasonal — December alone averages 69 mm while August barely receives 11 mm. Snowfall is heavy (261 cm of snow per year on average).

☀️ Summers

Warm

Highs near 27°C in July.

About 3 days a year above 32 °C

❄️ Winters

Very cold

Lows near −14°C in January.

About 220 freezing nights a year

🌧️ Rain & snow

Fairly dry

About 429 mm of rain a year, plus 261 cm of snow.

Snow falls through the winter months

⛅ Sky & trend

Partly cloudy

A roughly even mix of sun and cloud.

+0.6 °C vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation split into rain and snow · 1991–2020 normals · hover a month for the exact figures

Hours of sunshine per day

Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)

Sun Valley climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	0	2	6	12	17	21	27	26	21	14	6	0
Avg temp (°C)	−7	−5	−1	4	9	13	17	16	12	5	−1	−7
Avg low (°C)	−14	−12	−8	−3	1	4	7	6	2	−3	−8	−13
Precipitation (mm)	54	42	45	30	42	36	12	11	20	36	30	69
Snowfall (cm)	72	47	27	9	0	—	—	—	0	4	26	75

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°C)	0	2	6	12	17	21
Avg temp (°C)	−7	−5	−1	4	9	13
Avg low (°C)	−14	−12	−8	−3	1	4
Precipitation (mm)	54	42	45	30	42	36
Snowfall (cm)	72	47	27	9	0	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	27	26	21	14	6	0
Avg temp (°C)	17	16	12	5	−1	−7
Avg low (°C)	7	6	2	−3	−8	−13
Precipitation (mm)	12	11	20	36	30	69
Snowfall (cm)	—	—	0	4	26	75

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	9	8	8	6	7	7	4	4	4	5	6	10
Days with high ≥ 32°C (days)	—	—	—	—	—	0.2	2	0.9	0.0	—	—	—
Days with low ≤ 0°C (days)	31	27	30	24	12	4	1	1	8	23	28	30
Days with snowfall ≥ 2.5 cm (days)	7	5	3	1	0.1	—	—	—	—	0.5	3	8

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	9	8	8	6	7	7
Days with high ≥ 32°C (days)	—	—	—	—	—	0.2
Days with low ≤ 0°C (days)	31	27	30	24	12	4
Days with snowfall ≥ 2.5 cm (days)	7	5	3	1	0.1	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	4	4	4	5	6	10
Days with high ≥ 32°C (days)	2	0.9	0.0	—	—	—
Days with low ≤ 0°C (days)	1	1	8	23	28	30
Days with snowfall ≥ 2.5 cm (days)	—	—	—	0.5	3	8

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	59	61	64	63	61	50	35	35	39	48	58	61
Relative humidity (%)	84	82	74	64	58	51	39	36	41	54	70	83
Wind speed (m/s)	1.6	1.9	2.1	2.2	2.2	2.2	2.1	2.0	1.9	1.9	1.7	1.6

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	59	61	64	63	61	50
Relative humidity (%)	84	82	74	64	58	51
Wind speed (m/s)	1.6	1.9	2.1	2.2	2.2	2.2

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	35	35	39	48	58	61
Relative humidity (%)	39	36	41	54	70	83
Wind speed (m/s)	2.1	2.0	1.9	1.9	1.7	1.6

Methodology & sources

Temperature & precipitation — 1991–2020 normals computed from 29 years of daily observations at Ketchum RS, a weather station, about 2 km from the city centre. The underlying daily records come from NOAA's global station network.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →