Sun River (4 mi S), Montana climate: Climate normals at a NOAA weather station
Sun River (4 mi S)'s normal year runs from 13°F January nights to 83°F July afternoons, with 13.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.4°C, January lows of −11°C, July highs of 29°C, 339 mm of precipitation a year.
- NOAA stationSun River (4 mi S)
- Station IDUSC00248021
- Location47.48°N 111.74°W
- Elevation3,600 ft (1,097 m)
On October 23, the normal high in Sun River (4 mi S) is 54°F and the normal low 28°F, and the chance of measurable rain or snow is 16%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sun River (4 mi S).
- Jan 38° 13°
- Feb 39° 13°
- Mar 47° 20°
- Apr 56° 28°
- May 65° 36°
- Jun 73° 44°
- Jul 83° 48°
- Aug 82° 47°
- Sep 72° 40°
- Oct 58° 31°
- Nov 45° 21°
- Dec 37° 14°
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 Sun River (4 mi S) each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 13°F. The most precipitation falls in June (2.69 in), the least in December (0.39 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 38°F | 13°F | 25.1°F | 0.42 | 4 | <1 | 26 | 8 h 50 min |
| February | 39°F | 13°F | 25.9°F | 0.49 | 5 | <1 | 25 | 10 h 10 min |
| March | 47°F | 20°F | 33.4°F | 0.60 | 5 | <1 | 25 | 11 h 50 min |
| April | 56°F | 28°F | 42.1°F | 1.70 | 7 | <1 | 19 | 13 h 30 min |
| May | 65°F | 36°F | 50.5°F | 2.20 | 7 | <1 | 8 | 15 h |
| June | 73°F | 44°F | 58.2°F | 2.69 | 8 | 1 | <1 | 16 h |
| July | 83°F | 48°F | 65.7°F | 1.12 | 4 | 8 | <1 | 15 h 40 min |
| August | 82°F | 47°F | 64.3°F | 1.01 | 4 | 7 | <1 | 14 h 20 min |
| September | 72°F | 40°F | 55.6°F | 1.27 | 5 | 1 | 4 | 12 h 40 min |
| October | 58°F | 31°F | 44.3°F | 0.90 | 5 | <1 | 15 | 11 h |
| November | 45°F | 21°F | 33.1°F | 0.55 | 4 | <1 | 22 | 9 h 20 min |
| December | 37°F | 14°F | 25.4°F | 0.39 | 4 | <1 | 27 | 8 h 30 min |
| Year (annual) | 58°F | 29°F | 43.6°F | 13.34 | 62 | 18 | 170 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −11°C | −3.8°C | 11 mm |
| February | 4°C | −11°C | −3.4°C | 12 mm |
| March | 8°C | −7°C | 0.8°C | 15 mm |
| April | 13°C | −2°C | 5.6°C | 43 mm |
| May | 18°C | 2°C | 10.3°C | 56 mm |
| June | 23°C | 6°C | 14.6°C | 68 mm |
| July | 29°C | 9°C | 18.7°C | 28 mm |
| August | 28°C | 8°C | 17.9°C | 26 mm |
| September | 22°C | 4°C | 13.1°C | 32 mm |
| October | 14°C | −1°C | 6.8°C | 23 mm |
| November | 7°C | −6°C | 0.6°C | 14 mm |
| December | 3°C | −10°C | −3.7°C | 10 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Great Falls Weather Office (17 miles away), gets 69 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00248021; 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 Sun River (4 mi S)?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August 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 USC00248021.
When is the last frost at Sun River (4 mi S)?
In Sun River (4 mi S), the last spring frost (32°F) comes after June 2 in half of years and after June 21 in one year in ten; the first autumn frost comes before September 10 in half of years and before August 25 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 21 year in 10 after June 21; 9 in 10 after May 18
- First autumn frost, half of years before
- September 101 year in 10 before August 25; 9 in 10 before September 25
NOAA puts the median frost-free season at 96 days, and the season without a hard freeze (28°F) at 127 days.
A hard freeze (28°F) comes after May 18 in half of springs and before September 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sun River (4 mi S) in zone 4a in ZIP code 59483, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 3b: the coldest night of a typical year reaches −31°F (23 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 Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00248021; 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 at Sun River (4 mi S)?
In a normal year in Sun River (4 mi S), 18 days a year reach 90°F (1 of them 100°F or more), 170 nights fall to 32°F or colder and 62 days bring measurable precipitation.
- Days at 90°F or more
- 18a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 170a normal year
- Days that stay below freezing
- 35high of 32°F or less
- Days with 0.01 inch of precipitation
- 62a normal year
The highest temperature in this station's record (since 1943) is 111°F, on July 23, 2006; the lowest is −51°F, on December 29, 1968.
The wettest calendar year on that record is 1989, with 20.12 in; the snowiest season is 1966–67, with 93.8 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00248021; records: ACIS (NOAA Regional Climate Centers), station USC00248021. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Sun River (4 mi S)?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds at Sun River (4 mi S), 4.0 kWh per square metre a day. July is the sunniest month (87%) and December the cloudiest (66%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 71% | 1.5 |
| February | 73% | 2.5 |
| March | 71% | 3.6 |
| April | 69% | 4.8 |
| May | 71% | 5.8 |
| June | 76% | 6.6 |
| July | 87% | 7.2 |
| August | 85% | 5.9 |
| September | 78% | 4.3 |
| October | 72% | 2.7 |
| November | 68% | 1.6 |
| December | 66% | 1.2 |
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 Sun River (4 mi S) record?
A normal year at Sun River (4 mi S) brings 7,940 heating degree days, 48% more than the median U.S. place (5,373), and 178 cooling degree days, 80% 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 1,586 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,237 | 0 |
| February | 1,093 | 0 |
| March | 980 | 0 |
| April | 687 | 0 |
| May | 452 | 1 |
| June | 219 | 13 |
| July | 64 | 86 |
| August | 90 | 67 |
| September | 292 | 10 |
| October | 643 | 1 |
| November | 957 | 0 |
| December | 1,226 | 0 |
| Year (annual) | 7,940 | 178 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00248021. 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.
Have recent years at Sun River (4 mi S) been warmer than normal?
Over 46 complete years from 1955 to 2020, the station's annual mean temperature rose at a fitted 3.7°F per century (+0.21°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Sun River (4 mi S)'s climate compare?
Sun River (4 mi S) is warmer than 63 of the 141 places with their own NOAA record in Montana, and wetter than 37. Across the 7,247 U.S. stations with normals, its annual mean of 43.6°F is warmer than 14%.
In the Köppen classification computed from these normals, Sun River (4 mi S) 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 Sun River (4 mi S) share this climate record?
5 places have no NOAA station with 1991-2020 normals of their 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.
- Vaughn, MT970 people · 10 mi NE
- Fort Shaw, MT190 people · 4 mi W
- Sun River, MT62 people · 4 mi N
- Cascade Colony, MT49 people · 5 mi SW
- Fair Haven Colony, MT0 people · 7 mi SE
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 Sun River (4 mi S)'s climate
What is the coldest month at Sun River (4 mi S)?
January, with a normal high of 38°F and a normal low of 13°F. The warmest is July (83°F by day, 48°F at night).
Does it snow at Sun River (4 mi S)?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Great Falls Weather Office (17 miles away), records 69 inches of snow in a normal year.
What is the rainiest month at Sun River (4 mi S)?
June, with 2.69 in of precipitation in a normal year; the driest is December with 0.39 in.
What plant hardiness zone is Sun River (4 mi S) in?
The USDA's 2023 map puts Sun River (4 mi S) in zone 4a in ZIP code 59483, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −31°F (23 years, 1991-2020): zone 3b.
How late can frost come at Sun River (4 mi S)?
In half of years the last 32°F night comes after June 2; in one year in ten it comes after June 21. Waiting until June 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Fairfield, MT15 miles from this station, 44.4°F a year
- Great Falls, MT17 miles from this station, 44.6°F a year
- Cascade, MT18 miles from this station, 47.0°F a year
- Great Falls 16ST, MT21 miles from this station, 47.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made