Painted Desert Community Complex Historic District · Photo: National Park Service · Public domainSun Valley is among the driest of U.S. towns: 9 inches of precipitation a year
Midsummer highs settle at about 93°. The wettest month is August; the driest is June. By July afternoons alone, it runs hotter than 92% of U.S. towns. Warm coats and heating bills mark the months from November to March, when means dip under 50°.
A year in Sun Valley at a glance
Each month’s typical high and low, and what it brings.
What stands out about Sun Valley’s climate
Compared with towns across the U.S., with Sun Valley’s place in Arizona beside it.
What a year in Sun Valley feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 184 frost-free days a year
In half of years the last 32° night comes by April 22 and the first by October 24. Frost and day counts come from NOAA’s station at Holbrook, AZ, 10 miles from the town’s center, 190 ft lower.
The 2023 USDA map puts Sun Valley’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 4°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 4 inches of snow a winter
Snow, measured at Petrified Forest Np, AZ, falls mostly in January, March and December. Precipitation (rain plus melted snow) adds up to 9 inches a year; August is the wettest month and June the driest. Rain or snow falls on about 62 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Sun Valley
78% of the work is heating. Months averaging under 55° run from November through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Holbrook, AZ.
Living with Sun Valley’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
184 frost-free days in zone 7a. The last frost comes by Apr 22 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 24.
Months with highs of 62–84° and lows of 40° or more: May. 16 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Sun Valley from natural hazards, river flooding is the largest share (85%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Sun Valley and similar climates
TownRatings has no climate map of the towns around Sun Valley yet.
Climates most like Sun Valley’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Sun Valley, AZ | 21° | 93° | 9" | 3.5" |
| El Cerro Mission, NM | 21° | 93° | 10" | 5.1" |
| Fernley, NV | 25° | 93° | 6" | 4.5" |
| Star, ID | 24° | 93° | 11" | 7.4" |
| Fruitvale, CO | 19° | 94° | 10" | 13" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Sun Valley averaged 1.5° warmer than the 1900s. The biggest change is in March (+2.7°).
A bigger shift than in 62% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Sun Valley compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Sun Valley’s place among Arizona’s.
Sun Valley weather by month
Highs, lows and precipitation from NOAA’s grid at Sun Valley’s center; snow, wet days and snow on the ground from Petrified Forest Np, AZ. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 49° | 21° | 0.7" | 0.8" | 6 | 0 | 25° – 41° |
| February | 56° | 25° | 0.6" | 0.6" | 5 | 0 | 35° – 46° |
| March | 64° | 30° | 0.7" | 0.8" | 5 | 0 | 42° – 52° |
| April | 71° | 36° | 0.4" | 0.0" | 3 | 0 | 48° – 58° |
| May | 80° | 44° | 0.4" | 0.0" | 4 | 0 | 57° – 66° |
| June | 91° | 53° | 0.2" | 0.0" | 2 | 0 | 67° – 76° |
| July | 93° | 61° | 1.3" | 0.0" | 9 | 0 | 73° – 81° |
| August | 90° | 60° | 1.5" | 0.0" | 9 | 0 | 72° – 79° |
| September | 84° | 52° | 1.0" | 0.0" | 5 | 0 | 64° – 71° |
| October | 73° | 39° | 0.8" | 0.2" | 5 | 0 | 52° – 61° |
| November | 60° | 28° | 0.6" | 0.3" | 4 | 0 | 37° – 51° |
| December | 48° | 21° | 0.7" | 0.8" | 5 | 1 | 29° – 41° |
| Year | 72° | 39° | 8.7" | 3.5" | 62 | 2 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 25° to 41°. August is the most reliable, staying within 7°.
Where Sun Valley’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Sun Valley’s center.
- Snow: Petrified Forest Np, AZ.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Holbrook, AZ, 10 miles from the town’s center, 190 ft lower; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Sun Valley’s climate
What is the weather like in Sun Valley?
A typical July afternoon reaches 93°, a January night drops to 21°, and about 4 inches of snow falls in a normal winter. Colder January nights than 55% of U.S. towns; hotter July afternoons than 92% of U.S. towns.
How cold does it get in Sun Valley in winter?
January nights average 21°. About 137 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 25°.
How much snow does Sun Valley get?
About 3.5 inches in a normal winter at Petrified Forest Np, AZ, most of it in January, March and December, with snow on the ground about 2 days a year.
How hot does it get in Sun Valley?
July, with a typical high of 93° and a low of 61°. About 77 days a year reach 90° and 9 reach 100° (Holbrook, AZ).
When is the first and last frost in Sun Valley?
In half of years the last spring frost (32°) comes by April 22 and the first fall frost by October 24, about 184 frost-free days, at Holbrook, AZ.
What growing zone is Sun Valley in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 4°.
What is the best time of year to visit Sun Valley?
By one simple rule (highs of 62–84° and lows of 40° or more), May. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Sun Valley getting warmer?
Yes: 1991–2020 averaged 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 62% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Sun Valley.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.