United States · 1991–2020

Best time to visit
Sun Valley.

September leads for comfortable weather in Sun Valley: typically 27.8°C by day, 11.8°C at night, with 6 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high27.8°C

Typical low11.8°C

Rain in September6 mm

Comfort

September

September · May · June

82climate match

Beach

June

June · August · July

74climate match

Outdoors

October

October · May · April

93climate match

The weakest month is December, scoring 11 against September’s 82 — days reach only 7.1°C, 17° below the 24°C the score treats as ideal.

Month by month

The whole year,
without the guesswork.

The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.

Jan

147.8° / -2.3°

Feb

219.6° / -1.5°

Mar

4113.8° / 1.1°

Apr

5516.8° / 3.2°

May

8122.3° / 7.7°

Jun

8128.4° / 12.4°

Jul

6533.8° / 16.6°

Aug

7032.7° / 15.7°

Sep

8227.8° / 11.8°

Oct

7120.1° / 5.9°

Nov

3712.7° / 0.8°

Dec

117.1° / -2.7°

Monthly climate evidence for Sun Valley — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	7.8°C	-2.3°C	33 mm	4.8	9 h 39	14	Good coverage
February	9.6°C	-1.5°C	27 mm	4.7	10 h 38	21	Good coverage
March	13.8°C	1.1°C	18 mm	3.4	11 h 49	41	Good coverage
April	16.8°C	3.2°C	14 mm	2.9	13 h 11	55	Good coverage
May	22.3°C	7.7°C	15 mm	3.2	14 h 20	81	Strong coverage
June	28.4°C	12.4°C	12 mm	1.8	14 h 57	81	Strong coverage
July	33.8°C	16.6°C	8 mm	1.6	14 h 42	65	Strong coverage
August	32.7°C	15.7°C	6 mm	1.2	13 h 43	70	Strong coverage
September	27.8°C	11.8°C	6 mm	1.2	12 h 24	82	Strong coverage
October	20.1°C	5.9°C	16 mm	2.2	11 h 05	71	Strong coverage
November	12.7°C	0.8°C	19 mm	3.1	9 h 57	37	Strong coverage
December	7.1°C	-2.7°C	32 mm	4.9	9 h 23	11	Strong coverage

Records at RENO WFO, 1996–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	21.7°C31 Jan 2003	-15.6°C13 Jan 2007	32 mm8 Jan 2005	125 mm2017 · driest 0 mm in 2022	30
February	22.8°C22 Feb 2002	-13.9°C26 Feb 2011	37 mm13 Feb 2025	111 mm2017 · driest 0 mm in 2013	30
March	29.4°C20 Mar 2026	-10.0°C2 Mar 2023	27 mm1 Mar 2004	63 mm2024 · driest 0 mm in 2015	30
April	31.7°C22 Apr 2012	-7.2°C4 Apr 1999	20 mm9 Apr 2016	61 mm2006 · driest 0 mm in 2008	30
May	36.7°C28 May 2003	-3.9°C11 May 2000	22 mm16 May 1996	65 mm2023 · driest 0 mm in 2001	31
June	39.4°C20 Jun 2017	0.6°C8 Jun 2020	25 mm5 Jun 2011	42 mm1997 · driest 0 mm in 2010	31
July	42.2°C11 Jul 2002	5.6°C1 Jul 1997	28 mm14 Jul 2018	39 mm2015 · driest 0 mm in 2007	31
August	40.6°C2 Aug 2017	3.9°C25 Aug 2024	17 mm4 Aug 2014	38 mm2022 · driest 0 mm in 1997	30
September	39.4°C6 Sep 2022	-0.6°C28 Sep 2019	18 mm5 Sep 1998	60 mm1998 · driest 0 mm in 2006	30
October	33.3°C2 Oct 2024	-7.2°C30 Oct 2019	50 mm24 Oct 2021	82 mm2021 · driest 0 mm in 2019	30
November	25.0°C4 Nov 2020	-13.9°C24 Nov 2010	26 mm2 Nov 2015	56 mm2015 · driest 1 mm in 1999	30
December	18.3°C3 Dec 2007	-18.3°C8 Dec 2009	48 mm31 Dec 2022	119 mm2022 · driest 0 mm in 2011	30

Typical days per month at RENO WFO, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	23	1	4
February	0	0	19	<1	3
March	<1	0	13	<1	3
April	3	<1	8	<1	1
May	11	4	<1	<1	<1
June	23	14	0	<1	0
July	31	28	0	<1	0
August	30	26	0	<1	0
September	22	13	<1	<1	<1
October	7	<1	3	<1	<1
November	0	0	13	<1	1
December	0	0	24	<1	4

How often, not how much — every day in RENO WFO’s record sorted by what it was actually like, rather than averaged
Month	Warm & dry days	Wet days	Washouts	Week with 3+ wet days	Daytime mean has ranged
January	<1%	15%	3%	14%	3.8–11.1°C
February	1%	16%	3%	16%	7.1–12.6°C
March	16%	11%	1%	7%	10.7–17.2°C
April	35%	9%	<1%	5%	14.0–19.0°C
May	65%	10%	1%	9%	19.1–24.2°C
June	89%	6%	1%	4%	25.1–31.1°C
July	95%	5%	<1%	2%	32.5–35.6°C
August	95%	5%	<1%	2%	31.0–34.3°C
September	90%	5%	<1%	3%	25.5–29.6°C
October	56%	7%	2%	4%	17.6–23.3°C
November	11%	10%	2%	7%	9.6–14.7°C
December	0%	17%	3%	15%	5.8–9.6°C

A warm and dry day reaches 20°C with under 1 mm of rain; a wet day gets 1 mm or more; a washout gets 10 mm or more. The week column is the share of seven-day stretches in that month, across the station’s whole daily record, that contained three or more wet days — the odds a week-long trip is rained on repeatedly, counted rather than modelled. The last column is the 10th to 90th percentile of that month’s daytime average across individual years: a narrow band means the average is what you will get, a wide one means the average is a midpoint between years that felt quite different.

1997Each stripe is one year’s mean temperature against the 29-year average. Warmest: 2014. Coolest: 2010.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5513307
NOAA station: USC00266791 · RENO WFO
Station distance: 3.5 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 24 usable years
Daylight: Calculated from latitude 39.60°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Important limit: Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.

These places read the same station, so their numbers are identical — distance from RENO WFO is what differs

Reno→Mogul→Lawton→North Valley→Panther Valley→Raleigh Heights→

Or put two places side by side: Sun Valley vs Reno

Best time to visitSun Valley.