Dewey, Utah climate: Climate normals at a NOAA weather station
Dewey's normal year runs from 16°F January nights to 101°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.8°C, January lows of −9°C, July highs of 38°C.
- NOAA stationDewey
- Station IDUSC00422150
- Location38.81°N 109.30°W
- Elevation4,120 ft (1,256 m)
On October 23, the normal high in Dewey is 70°F and the normal low 31°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Dewey.
- Jan 42° 16°
- Feb 52° 24°
- Mar 65° 31°
- Apr 73° 37°
- May 83° 45°
- Jun 95° 53°
- Jul 101° 60°
- Aug 98° 58°
- Sep 90° 48°
- Oct 74° 34°
- Nov 57° 24°
- Dec 44° 17°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Dewey each month?
July is the warmest month, with normal highs of 101°F; January the coldest, with normal lows of 16°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 42°F | 16°F | 29.0°F | – | <1 | 30 | 9 h 40 min |
| February | 52°F | 24°F | 37.8°F | – | <1 | 25 | 10 h 40 min |
| March | 65°F | 31°F | 47.6°F | – | <1 | 20 | 11 h 50 min |
| April | 73°F | 37°F | 54.8°F | – | 1 | 9 | 13 h 10 min |
| May | 83°F | 45°F | 64.3°F | – | 7 | 1 | 14 h 20 min |
| June | 95°F | 53°F | 74.1°F | – | 22 | <1 | 14 h 50 min |
| July | 101°F | 60°F | 80.4°F | – | 30 | <1 | 14 h 40 min |
| August | 98°F | 58°F | 78.2°F | – | 29 | <1 | 13 h 40 min |
| September | 90°F | 48°F | 68.9°F | – | 15 | 1 | 12 h 30 min |
| October | 74°F | 34°F | 54.2°F | – | 1 | 12 | 11 h 20 min |
| November | 57°F | 24°F | 40.7°F | – | <1 | 25 | 10 h 10 min |
| December | 44°F | 17°F | 30.6°F | – | <1 | 31 | 9 h 30 min |
| Year (annual) | 73°F | 37°F | 55.0°F | – | 104 | 154 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | 6°C | −9°C | −1.7°C |
| February | 11°C | −5°C | 3.2°C |
| March | 18°C | −1°C | 8.7°C |
| April | 23°C | 3°C | 12.7°C |
| May | 28°C | 7°C | 17.9°C |
| June | 35°C | 12°C | 23.4°C |
| July | 38°C | 16°C | 26.9°C |
| August | 37°C | 15°C | 25.7°C |
| September | 32°C | 9°C | 20.5°C |
| October | 23°C | 1°C | 12.3°C |
| November | 14°C | −5°C | 4.8°C |
| December | 7°C | −8°C | −0.8°C |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Castle Valley station (12 miles away), gets 15 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00422150; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Dewey?
Normal highs sit between 65°F and 85°F in April, May and October.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00422150.
When is the last frost at Dewey?
In Dewey, the last spring frost (32°F) comes after April 27 in half of years and after May 9 in one year in ten; the first autumn frost comes before October 9 in half of years and before September 28 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 271 year in 10 after May 9; 9 in 10 after April 13
- First autumn frost, half of years before
- October 91 year in 10 before September 28; 9 in 10 before October 20
NOAA puts the median frost-free season at 165 days, and the season without a hard freeze (28°F) at 185 days.
A hard freeze (28°F) comes after April 14 in half of springs and before October 18 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Dewey in zone 6b in ZIP code 84515, the nearest ZIP area.
Frost dates for every NOAA station in Utah · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00422150; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Dewey?
In a normal year in Dewey, 104 days a year reach 90°F (39 of them 100°F or more) and 154 nights fall to 32°F or colder.
- Days at 90°F or more
- 104a normal year
- Days at 100°F or more
- 39a normal year
- Nights at 32°F or colder
- 154a normal year
- Days that stay below freezing
- 8high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00422150.
How sunny is it at Dewey?
Over a year 85% of the sunlight that would reach the ground under clear skies gets through the clouds at Dewey, 5.3 kWh per square metre a day. June is the sunniest month (91%) and December the cloudiest (76%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 78% | 2.7 |
| February | 77% | 3.6 |
| March | 83% | 5.2 |
| April | 84% | 6.5 |
| May | 86% | 7.5 |
| June | 91% | 8.3 |
| July | 88% | 7.5 |
| August | 87% | 6.7 |
| September | 89% | 5.8 |
| October | 87% | 4.3 |
| November | 84% | 3.1 |
| December | 76% | 2.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Dewey record?
A normal year at Dewey brings 4,991 heating degree days, 7% fewer than the median U.S. place (5,373), and 1,392 cooling degree days, 53% more than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,938 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,116 | 0 |
| February | 762 | 0 |
| March | 540 | 0 |
| April | 312 | 6 |
| May | 90 | 67 |
| June | 5 | 278 |
| July | 0 | 477 |
| August | 1 | 410 |
| September | 33 | 151 |
| October | 339 | 3 |
| November | 730 | 0 |
| December | 1,065 | 0 |
| Year (annual) | 4,991 | 1,392 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00422150. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Dewey's climate compare?
Dewey is warmer than 89 of the 97 places with their own NOAA record in Utah. Across the 7,247 U.S. stations with normals, its annual mean of 55.0°F is warmer than 60%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Questions about Dewey's climate
What is the coldest month at Dewey?
January, with a normal high of 42°F and a normal low of 16°F. The warmest is July (101°F by day, 60°F at night).
Does it snow at Dewey?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Castle Valley station (12 miles away), records 15 inches of snow in a normal year.
What plant hardiness zone is Dewey in?
The USDA's 2023 map puts Dewey in zone 6b in ZIP code 84515, the nearest ZIP area.
How late can frost come at Dewey?
In half of years the last 32°F night comes after April 27; in one year in ten it comes after May 9. Waiting until May 9 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Utah climateThe statewide normals and every place in the state
- Castle Valley, UT14 miles from this station, 54.7°F a year
- Glade Park (17 mi W), CO17 miles from this station, 47.1°F a year
- Gateway (1 mi ENE), CO21 miles from this station, 56.1°F a year
- Moab, UT21 miles from this station, 57.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made