Alton, Utah climate: Normal weather by month, frost dates and records
Alton's normal year runs from 18°F December nights to 85°F July afternoons, with 17.3 inches of precipitation and 78 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.5°C, December lows of −8°C, July highs of 30°C, 439 mm of precipitation a year.
- NOAA stationAlton
- Station IDUSC00420086
- Location37.44°N 112.48°W
- Elevation7,098 ft (2,164 m)
- Population116
On October 23, the normal high in Alton is 61°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 Alton.
- Jan 41° 18°
- Feb 43° 19°
- Mar 52° 24°
- Apr 60° 29°
- May 69° 35°
- Jun 81° 43°
- Jul 85° 51°
- Aug 83° 50°
- Sep 76° 43°
- Oct 64° 34°
- Nov 51° 24°
- Dec 41° 18°
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 Alton each month?
July is the warmest month, with normal highs of 85°F; December the coldest, with normal lows of 18°F. The most precipitation falls in February (2.07 in), the least in June (0.41 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 41°F | 18°F | 29.6°F | 2.03 | 17.8 | 6 | <1 | 30 | 9 h 50 min |
| February | 43°F | 19°F | 31.4°F | 2.07 | 18.7 | 7 | <1 | 27 | 10 h 50 min |
| March | 52°F | 24°F | 38.0°F | 1.51 | 12.6 | 6 | <1 | 28 | 11 h 50 min |
| April | 60°F | 29°F | 44.5°F | 0.82 | 5.2 | 5 | <1 | 22 | 13 h 10 min |
| May | 69°F | 35°F | 52.3°F | 0.87 | 0.3 | 5 | <1 | 10 | 14 h 10 min |
| June | 81°F | 43°F | 61.7°F | 0.41 | 0.4 | 2 | 2 | 1 | 14 h 40 min |
| July | 85°F | 51°F | 68.2°F | 1.17 | 0.0 | 7 | 7 | <1 | 14 h 30 min |
| August | 83°F | 50°F | 66.6°F | 1.87 | 0.0 | 8 | 3 | <1 | 13 h 40 min |
| September | 76°F | 43°F | 59.4°F | 1.70 | 0.0 | 6 | <1 | 1 | 12 h 30 min |
| October | 64°F | 34°F | 48.8°F | 1.80 | 2.0 | 5 | <1 | 13 | 11 h 20 min |
| November | 51°F | 24°F | 37.7°F | 1.22 | 6.4 | 4 | <1 | 26 | 10 h 10 min |
| December | 41°F | 18°F | 29.4°F | 1.83 | 14.1 | 6 | <1 | 31 | 9 h 40 min |
| Year (annual) | 62°F | 32°F | 47.3°F | 17.30 | 77.5 | 66 | 12 | 190 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −8°C | −1.3°C | 52 mm | 45 cm |
| February | 6°C | −7°C | −0.3°C | 53 mm | 47 cm |
| March | 11°C | −4°C | 3.3°C | 38 mm | 32 cm |
| April | 16°C | −2°C | 6.9°C | 21 mm | 13 cm |
| May | 21°C | 2°C | 11.3°C | 22 mm | 1 cm |
| June | 27°C | 6°C | 16.5°C | 10 mm | 1 cm |
| July | 30°C | 11°C | 20.1°C | 30 mm | 0 cm |
| August | 28°C | 10°C | 19.2°C | 47 mm | 0 cm |
| September | 24°C | 6°C | 15.2°C | 43 mm | 0 cm |
| October | 18°C | 1°C | 9.3°C | 46 mm | 5 cm |
| November | 11°C | −4°C | 3.2°C | 31 mm | 16 cm |
| December | 5°C | −8°C | −1.4°C | 46 mm | 36 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00420086; 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 Alton?
Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, June has the fewest days with rain (2).
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 USC00420086.
When is the last frost in Alton?
In Alton, the last spring frost (32°F) comes after June 1 in half of years and after June 15 in one year in ten; the first autumn frost comes before September 30 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
- June 11 year in 10 after June 15; 9 in 10 after May 16
- First autumn frost, half of years before
- September 301 year in 10 before September 16; 9 in 10 before October 12
NOAA puts the median frost-free season at 120 days, and the season without a hard freeze (28°F) at 147 days.
A hard freeze (28°F) comes after May 17 in half of springs and before October 11 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alton in zone 6a in ZIP code 84710, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Alton's NOAA station is in zone 6b: the coldest night of a typical year reaches −3°F (28 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Utah · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00420086; 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 Alton?
In a normal year in Alton, 12 days a year reach 90°F, 190 nights fall to 32°F or colder and 66 days bring measurable precipitation.
- Days at 90°F or more
- 12a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 190a normal year
- Days that stay below freezing
- 16high of 32°F or less
- Days with 0.01 inch of precipitation
- 66a normal year
- Days with 1 inch of snow or more
- 20a normal year
The highest temperature in this station's record (since 1915) is 101°F, on July 10, 2021; the lowest is −24°F, on December 22, 1990.
The wettest calendar year on that record is 1969, with 25.82 in; the snowiest season is 1992–93, with 200.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00420086; records: ACIS (NOAA Regional Climate Centers), station USC00420086. Records use complete months only; a month missing more than three days is left out.
How sunny is Alton?
Over a year 84% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Alton, 5.3 kWh per square metre a day. June is the sunniest month (91%) and December the cloudiest (77%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 80% | 2.9 |
| February | 78% | 3.7 |
| March | 81% | 5.1 |
| April | 83% | 6.5 |
| May | 85% | 7.4 |
| June | 91% | 8.3 |
| July | 82% | 7.1 |
| August | 84% | 6.5 |
| September | 87% | 5.8 |
| October | 86% | 4.4 |
| November | 83% | 3.2 |
| December | 77% | 2.5 |
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 Alton need?
A normal year in Alton brings 6,661 heating degree days, 24% more than the median U.S. place (5,373), and 237 cooling degree days, 74% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,945 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,097 | 0 |
| February | 941 | 0 |
| March | 839 | 0 |
| April | 615 | 0 |
| May | 395 | 2 |
| June | 129 | 31 |
| July | 18 | 119 |
| August | 28 | 77 |
| September | 176 | 8 |
| October | 502 | 0 |
| November | 818 | 0 |
| December | 1,104 | 0 |
| Year (annual) | 6,661 | 237 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00420086. 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 Alton been warmer than normal lately?
2025 averaged 49.8°F, 2.5°F above the 1991-2020 normal of 47.3°F. 3 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 49.1°F | +1.8°F | 18.77 | 63.0 |
| 2022 | 47.2°F | −0.1°F | 17.93 | 53.0 |
| 2023 | 45.6°F | −1.7°F | 24.86 | 124.2 |
| 2024 | 49.3°F | +2.0°F | 15.25 | 52.5 |
| 2025 | 49.8°F | +2.5°F | 16.53 | 45.3 |
Over 80 complete years from 1916 to 2025, the station's annual mean temperature rose at a fitted 2.3°F per century (+0.13°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00420086; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Alton's climate compare?
Alton is warmer than 32 of the other 96 places with their own NOAA record in Utah, and wetter than 75. Across the 7,247 U.S. stations with normals, its annual mean of 47.3°F is warmer than 29%.
In the Köppen classification computed from these normals, Alton is Dsb: continental, dry-summer, warm summer. 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.
Questions about Alton's climate
What is the coldest month in Alton?
December, with a normal high of 41°F and a normal low of 18°F. The warmest is July (85°F by day, 51°F at night).
Does it snow in Alton?
Yes: 78 inches in a normal year, falling on 24 days with 0.1 inch or more, the most in February (18.7 inches).
What is the rainiest month in Alton?
February, with 2.07 in of precipitation in a normal year; the driest is June with 0.41 in.
What plant hardiness zone is Alton in?
The USDA's 2023 map puts Alton in zone 6a in ZIP code 84710, the nearest ZIP area. By the same method at Alton's NOAA station, the coldest night of a typical year reaches −3°F (28 years, 1991-2020): zone 6b.
How late can frost come in Alton?
In half of years the last 32°F night comes after June 1; in one year in ten it comes after June 15. Waiting until June 15 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Utah climateThe statewide normals and every place in the state
- Orderville, UT14 miles from this station, 51.8°F a year
- Hatch, UT15 miles from this station, 43.9°F a year
- Bryce Canyon National Park Headquarters, UT22 miles from this station, 44.4°F a year
- Cedar Breaks National Monument, UT23 miles from this station, 41.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made