Delta, Utah climate: Normal weather by month, frost dates and records
Delta's normal year runs from 15°F December nights to 95°F July afternoons, with 8.0 inches of precipitation and 25 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.3°C, December lows of −10°C, July highs of 35°C, 203 mm of precipitation a year.
- NOAA stationDelta
- Station IDUSW00023162
- Location39.34°N 112.59°W
- Elevation4,620 ft (1,408 m)
- Population3,730
On October 23, the normal high in Delta is 64°F and the normal low 31°F, and the chance of measurable rain or snow is 15%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Delta.
- Jan 39° 16°
- Feb 47° 21°
- Mar 58° 27°
- Apr 65° 33°
- May 76° 41°
- Jun 87° 49°
- Jul 95° 57°
- Aug 93° 56°
- Sep 82° 46°
- Oct 68° 33°
- Nov 51° 23°
- Dec 39° 15°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Delta each month?
July is the warmest month, with normal highs of 95°F; December the coldest, with normal lows of 15°F. The most precipitation falls in April (0.94 in), the least in July (0.35 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 39°F | 16°F | 27.4°F | 0.63 | 5.5 | 6 | <1 | 30 | 9 h 40 min |
| February | 47°F | 21°F | 33.5°F | 0.64 | 5.3 | 6 | <1 | 26 | 10 h 40 min |
| March | 58°F | 27°F | 42.6°F | 0.80 | 3.9 | 6 | <1 | 25 | 11 h 50 min |
| April | 65°F | 33°F | 48.8°F | 0.94 | 2.2 | 6 | <1 | 17 | 13 h 10 min |
| May | 76°F | 41°F | 58.2°F | 0.92 | 0.0 | 6 | 3 | 4 | 14 h 20 min |
| June | 87°F | 49°F | 68.0°F | 0.48 | 0.0 | 3 | 13 | <1 | 15 h |
| July | 95°F | 57°F | 76.2°F | 0.35 | 0.0 | 4 | 27 | <1 | 14 h 40 min |
| August | 93°F | 56°F | 74.2°F | 0.54 | 0.0 | 5 | 24 | <1 | 13 h 50 min |
| September | 82°F | 46°F | 63.9°F | 0.71 | 0.0 | 4 | 7 | 2 | 12 h 30 min |
| October | 68°F | 33°F | 50.4°F | 0.91 | 0.8 | 5 | 1 | 16 | 11 h 10 min |
| November | 51°F | 23°F | 37.1°F | 0.50 | 3.2 | 4 | <1 | 27 | 10 h |
| December | 39°F | 15°F | 27.1°F | 0.59 | 4.4 | 5 | <1 | 30 | 9 h 30 min |
| Year (annual) | 67°F | 35°F | 50.6°F | 8.01 | 25.3 | 60 | 74 | 176 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 4°C | −9°C | −2.6°C | 16 mm | 14 cm |
| February | 8°C | −6°C | 0.8°C | 16 mm | 13 cm |
| March | 14°C | −3°C | 5.9°C | 20 mm | 10 cm |
| April | 18°C | 0°C | 9.3°C | 24 mm | 6 cm |
| May | 24°C | 5°C | 14.6°C | 23 mm | 0 cm |
| June | 30°C | 10°C | 20.0°C | 12 mm | 0 cm |
| July | 35°C | 14°C | 24.6°C | 9 mm | 0 cm |
| August | 34°C | 13°C | 23.4°C | 14 mm | 0 cm |
| September | 28°C | 8°C | 17.7°C | 18 mm | 0 cm |
| October | 20°C | 1°C | 10.2°C | 23 mm | 2 cm |
| November | 11°C | −5°C | 2.8°C | 13 mm | 8 cm |
| December | 4°C | −10°C | −2.7°C | 15 mm | 11 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023162; 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.
When is the best weather to visit Delta?
Normal highs sit between 65°F and 85°F in May, September and October. Of those, September has the fewest days with rain (4).
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 USW00023162.
When is the last frost in Delta?
In Delta, the last spring frost (32°F) comes after May 16 in half of years and after June 5 in one year in ten; the first autumn frost comes before September 29 in half of years and before September 16 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
- May 161 year in 10 after June 5; 9 in 10 after April 29
- First autumn frost, half of years before
- September 291 year in 10 before September 16; 9 in 10 before October 11
NOAA puts the median frost-free season at 137 days, and the season without a hard freeze (28°F) at 160 days.
A hard freeze (28°F) comes after May 2 in half of springs and before October 9 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Delta in zone 6a in ZIP code 84624, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Delta's NOAA station is in zone 6a: the coldest night of a typical year reaches −9°F (25 complete years).
Frost dates for every NOAA station in Utah · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00023162; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 in Delta?
In a normal year in Delta, 74 days a year reach 90°F (16 of them 100°F or more), 176 nights fall to 32°F or colder and 60 days bring measurable precipitation.
- Days at 90°F or more
- 74a normal year
- Days at 100°F or more
- 16a normal year
- Nights at 32°F or colder
- 176a normal year
- Days that stay below freezing
- 17high of 32°F or less
- Days with 0.01 inch of precipitation
- 60a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1965) is 110°F, on July 13, 2002; the lowest is −30°F, on December 23, 1990.
The wettest calendar year on that record is 1998, with 13.44 in; the snowiest season is 1978–79, with 49.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00023162; records: ACIS (NOAA Regional Climate Centers), station USW00023162. Records use complete months only; a month missing more than three days is left out.
How sunny is Delta?
Over a year 83% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Delta, 5.0 kWh per square metre a day. September is the sunniest month (89%) and December the cloudiest (69%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 2.4 |
| February | 72% | 3.2 |
| March | 77% | 4.7 |
| April | 79% | 6.0 |
| May | 83% | 7.1 |
| June | 89% | 8.0 |
| July | 88% | 7.5 |
| August | 88% | 6.8 |
| September | 89% | 5.7 |
| October | 85% | 4.1 |
| November | 78% | 2.7 |
| December | 69% | 2.0 |
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 much heating and cooling does Delta need?
A normal year in Delta brings 6,093 heating degree days, 13% more than the median U.S. place (5,373), and 882 cooling degree days, 3% fewer 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 3,015 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,166 | 0 |
| February | 881 | 0 |
| March | 696 | 0 |
| April | 488 | 1 |
| May | 234 | 24 |
| June | 54 | 144 |
| July | 2 | 351 |
| August | 4 | 291 |
| September | 103 | 70 |
| October | 454 | 3 |
| November | 837 | 0 |
| December | 1,175 | 0 |
| Year (annual) | 6,093 | 882 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023162. 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.
Has Delta been warmer than normal lately?
2025 averaged 54.6°F, 4.0°F above the 1991-2020 normal of 50.6°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 53.4°F | +2.8°F | 12.49 | 15.0 |
| 2023 | 50.9°F | +0.3°F | 6.71 | 25.0 |
| 2024 | 53.9°F | +3.3°F | 10.15 | 8.0 |
| 2025 | 54.6°F | +4.0°F | 6.13 | 3.0 |
Over 68 complete years from 1941 to 2025, the station's annual mean temperature rose at a fitted 3.1°F per century (+0.17°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00023162; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Delta's climate compare?
Delta is warmer than 57 of the other 96 places with their own NOAA record in Utah, and wetter than 9. Across the 7,247 U.S. stations with normals, its annual mean of 50.6°F is warmer than 43%.
In the Köppen classification computed from these normals, Delta is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Delta share this climate record?
Sutherland has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Sutherland, UT141 people · 5 mi NW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Delta's climate
What is the coldest month in Delta?
December, with a normal high of 39°F and a normal low of 15°F. The warmest is July (95°F by day, 57°F at night).
Does it snow in Delta?
Yes: 25 inches in a normal year, falling on 16 days with 0.1 inch or more, the most in January (5.5 inches).
What is the rainiest month in Delta?
April, with 0.94 in of precipitation in a normal year; the driest is July with 0.35 in.
What plant hardiness zone is Delta in?
The USDA's 2023 map puts Delta in zone 6a in ZIP code 84624, the nearest ZIP area. By the same method at Delta's NOAA station, the coldest night of a typical year reaches −9°F (25 years, 1991-2020): zone 6a.
How late can frost come in Delta?
In half of years the last 32°F night comes after May 16; in one year in ten it comes after June 5. Waiting until June 5 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Utah climateThe statewide normals and every place in the state
- Deseret, UT5 miles from this station, 51.0°F a year
- Oak City, UT16 miles from this station, 52.3°F a year
- Scipio, UT26 miles from this station, 49.5°F a year
- Fillmore, UT30 miles from this station, 51.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made