Fort Benton, Montana climate: Normal weather by month, frost dates and records
Fort Benton's normal year runs from 10°F January nights to 86°F July afternoons, with 13.2 inches of precipitation and 38 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.4°C, January lows of −12°C, July highs of 30°C, 336 mm of precipitation a year.
- NOAA stationFort Benton
- Station IDUSC00243113
- Location47.83°N 110.66°W
- Elevation2,649 ft (807 m)
- Population1,422
On October 22, the normal high in Fort Benton is 57°F and the normal low 28°F, and the chance of measurable rain or snow is 21%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Fort Benton.
- Jan 35° 10°
- Feb 38° 13°
- Mar 48° 20°
- Apr 59° 31°
- May 68° 41°
- Jun 76° 49°
- Jul 86° 54°
- Aug 86° 52°
- Sep 74° 42°
- Oct 60° 31°
- Nov 47° 21°
- Dec 37° 13°
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 Fort Benton each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 10°F. The most precipitation falls in June (2.62 in), the least in February (0.44 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 35°F | 10°F | 22.3°F | 0.52 | 7.9 | 5 | <1 | 28 | 8 h 50 min |
| February | 38°F | 13°F | 25.3°F | 0.44 | 6.9 | 6 | <1 | 26 | 10 h 10 min |
| March | 48°F | 20°F | 34.3°F | 0.56 | 4.3 | 6 | <1 | 27 | 11 h 50 min |
| April | 59°F | 31°F | 44.6°F | 1.48 | 3.0 | 8 | <1 | 16 | 13 h 40 min |
| May | 68°F | 41°F | 54.4°F | 2.08 | 0.3 | 10 | 1 | 4 | 15 h 10 min |
| June | 76°F | 49°F | 62.5°F | 2.62 | 0.0 | 11 | 2 | <1 | 16 h |
| July | 86°F | 54°F | 70.3°F | 1.19 | 0.0 | 6 | 13 | <1 | 15 h 40 min |
| August | 86°F | 52°F | 68.8°F | 1.16 | 0.0 | 6 | 12 | <1 | 14 h 20 min |
| September | 74°F | 42°F | 58.3°F | 1.20 | 0.3 | 7 | 3 | 2 | 12 h 40 min |
| October | 60°F | 31°F | 45.2°F | 0.92 | 1.9 | 7 | <1 | 16 | 11 h |
| November | 47°F | 21°F | 33.7°F | 0.58 | 5.7 | 6 | <1 | 25 | 9 h 20 min |
| December | 37°F | 13°F | 24.9°F | 0.47 | 7.9 | 5 | <1 | 28 | 8 h 30 min |
| Year (annual) | 59°F | 31°F | 45.4°F | 13.22 | 38.2 | 82 | 31 | 173 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 1°C | −12°C | −5.4°C | 13 mm | 20 cm |
| February | 3°C | −11°C | −3.7°C | 11 mm | 18 cm |
| March | 9°C | −6°C | 1.3°C | 14 mm | 11 cm |
| April | 15°C | −1°C | 7.0°C | 38 mm | 8 cm |
| May | 20°C | 5°C | 12.4°C | 53 mm | 1 cm |
| June | 25°C | 9°C | 16.9°C | 67 mm | 0 cm |
| July | 30°C | 12°C | 21.3°C | 30 mm | 0 cm |
| August | 30°C | 11°C | 20.4°C | 29 mm | 0 cm |
| September | 23°C | 6°C | 14.6°C | 30 mm | 1 cm |
| October | 16°C | −1°C | 7.3°C | 23 mm | 5 cm |
| November | 8°C | −6°C | 0.9°C | 15 mm | 14 cm |
| December | 3°C | −10°C | −3.9°C | 12 mm | 20 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00243113; 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 Fort Benton?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (7).
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 USC00243113.
When is the last frost in Fort Benton?
In Fort Benton, the last spring frost (32°F) comes after May 15 in half of years and after May 30 in one year in ten; the first autumn frost comes before September 22 in half of years and before September 7 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 151 year in 10 after May 30; 9 in 10 after May 3
- First autumn frost, half of years before
- September 221 year in 10 before September 7; 9 in 10 before October 4
NOAA puts the median frost-free season at 129 days, and the season without a hard freeze (28°F) at 149 days.
A hard freeze (28°F) comes after May 4 in half of springs and before October 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Fort Benton in zone 4a in ZIP code 59442, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Fort Benton's NOAA station is in zone 4a: the coldest night of a typical year reaches −27°F (23 complete years).
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00243113; 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 Fort Benton?
In a normal year in Fort Benton, 31 days a year reach 90°F (3 of them 100°F or more), 173 nights fall to 32°F or colder and 82 days bring measurable precipitation.
- Days at 90°F or more
- 31a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 173a normal year
- Days that stay below freezing
- 40high of 32°F or less
- Days with 0.01 inch of precipitation
- 82a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in this station's record (since 1894) is 109°F, on August 12, 1940; the lowest is −49°F, on January 24, 1969.
The wettest calendar year on that record is 1975, with 25.79 in; the snowiest season is 1958–59, with 114.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00243113; records: ACIS (NOAA Regional Climate Centers), station USC00243113. Records use complete months only; a month missing more than three days is left out.
How sunny is Fort Benton?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Fort Benton, 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 much heating and cooling does Fort Benton need?
A normal year in Fort Benton brings 7,545 heating degree days, 40% more than the median U.S. place (5,373), and 428 cooling degree days, 53% 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 2,164 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,322 | 0 |
| February | 1,110 | 0 |
| March | 953 | 0 |
| April | 612 | 0 |
| May | 335 | 8 |
| June | 122 | 46 |
| July | 24 | 187 |
| August | 43 | 161 |
| September | 228 | 25 |
| October | 615 | 1 |
| November | 938 | 0 |
| December | 1,243 | 0 |
| Year (annual) | 7,545 | 428 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00243113. 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 Fort Benton been warmer than normal lately?
2025 averaged 46.9°F, 1.5°F above the 1991-2020 normal of 45.4°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 46.8°F | +1.4°F | 9.77 | 43.1 |
| 2022 | 45.6°F | +0.2°F | 11.25 | 48.2 |
| 2023 | 48.3°F | +2.9°F | 14.70 | 26.3 |
| 2024 | 46.5°F | +1.1°F | 17.79 | 40.4 |
| 2025 | 46.9°F | +1.5°F | 13.79 | 43.7 |
Over 76 complete years from 1902 to 2025, the station's annual mean temperature rose at a fitted 2.6°F per century (+0.14°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00243113; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Fort Benton's climate compare?
Fort Benton is warmer than 101 of the other 140 places with their own NOAA record in Montana, and wetter than 34. Across the 7,247 U.S. stations with normals, its annual mean of 45.4°F is warmer than 21%.
In the Köppen classification computed from these normals, Fort Benton 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 Fort Benton share this climate record?
Carter 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.
- Carter, MT118 people · 13 mi W
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 Fort Benton's climate
What is the coldest month in Fort Benton?
January, with a normal high of 35°F and a normal low of 10°F. The warmest is July (86°F by day, 54°F at night).
Does it snow in Fort Benton?
Yes: 38 inches in a normal year, falling on 25 days with 0.1 inch or more, the most in January (7.9 inches).
What is the rainiest month in Fort Benton?
June, with 2.62 in of precipitation in a normal year; the driest is February with 0.44 in.
What plant hardiness zone is Fort Benton in?
The USDA's 2023 map puts Fort Benton in zone 4a in ZIP code 59442, the nearest ZIP area. By the same method at Fort Benton's NOAA station, the coldest night of a typical year reaches −27°F (23 years, 1991-2020): zone 4a.
How late can frost come in Fort Benton?
In half of years the last 32°F night comes after May 15; in one year in ten it comes after May 30. Waiting until May 30 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Loma, MT11 miles from this station, 44.8°F a year
- Highwood, MT13 miles from this station, 46.7°F a year
- Shonkin (7 mi S), MT21 miles from this station, 44.1°F a year
- Geraldine, MT24 miles from this station, 46.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made