Fairfield, Montana climate: Normal weather by month, frost dates and records
Fairfield's normal year runs from 17°F January nights to 80°F July afternoons, with 12.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.9°C, January lows of −9°C, July highs of 27°C, 314 mm of precipitation a year.
- NOAA stationFairfield
- Station IDUSC00242857
- Location47.62°N 111.99°W
- Elevation3,983 ft (1,214 m)
- Population794
On October 22, the normal high in Fairfield is 52°F and the normal low 32°F, and the chance of measurable rain or snow is 13%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Fairfield.
- Jan 36° 17°
- Feb 36° 17°
- Mar 45° 24°
- Apr 53° 32°
- May 62° 41°
- Jun 70° 48°
- Jul 80° 53°
- Aug 79° 52°
- Sep 69° 44°
- Oct 55° 34°
- Nov 43° 25°
- Dec 35° 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 Fairfield each month?
July is the warmest month, with normal highs of 80°F; January the coldest, with normal lows of 17°F. The most precipitation falls in June (2.63 in), the least in December (0.33 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 36°F | 17°F | 26.1°F | 0.34 | 4 | <1 | 27 | 8 h 50 min |
| February | 36°F | 17°F | 26.8°F | 0.43 | 5 | <1 | 25 | 10 h 10 min |
| March | 45°F | 24°F | 34.3°F | 0.60 | 6 | <1 | 24 | 11 h 50 min |
| April | 53°F | 32°F | 42.2°F | 1.36 | 7 | <1 | 16 | 13 h 30 min |
| May | 62°F | 41°F | 51.5°F | 2.12 | 8 | <1 | 4 | 15 h 10 min |
| June | 70°F | 48°F | 58.5°F | 2.63 | 9 | <1 | <1 | 16 h |
| July | 80°F | 53°F | 66.5°F | 1.08 | 6 | 4 | <1 | 15 h 40 min |
| August | 79°F | 52°F | 65.5°F | 1.05 | 6 | 3 | <1 | 14 h 20 min |
| September | 69°F | 44°F | 56.3°F | 1.23 | 6 | 1 | 2 | 12 h 40 min |
| October | 55°F | 34°F | 44.6°F | 0.74 | 4 | <1 | 13 | 11 h |
| November | 43°F | 25°F | 33.8°F | 0.46 | 4 | <1 | 22 | 9 h 20 min |
| December | 35°F | 18°F | 26.6°F | 0.33 | 4 | <1 | 27 | 8 h 30 min |
| Year (annual) | 55°F | 34°F | 44.4°F | 12.37 | 69 | 8 | 160 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 2°C | −9°C | −3.3°C | 9 mm |
| February | 2°C | −8°C | −2.9°C | 11 mm |
| March | 7°C | −5°C | 1.3°C | 15 mm |
| April | 12°C | 0°C | 5.7°C | 35 mm |
| May | 17°C | 5°C | 10.8°C | 54 mm |
| June | 21°C | 9°C | 14.7°C | 67 mm |
| July | 27°C | 12°C | 19.2°C | 27 mm |
| August | 26°C | 11°C | 18.6°C | 27 mm |
| September | 20°C | 7°C | 13.5°C | 31 mm |
| October | 13°C | 1°C | 7.0°C | 19 mm |
| November | 6°C | −4°C | 1.0°C | 12 mm |
| December | 2°C | −8°C | −3.0°C | 8 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Choteau (17 miles away), gets 48 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00242857; 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 Fairfield?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, September has the fewest days with rain (6).
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 USC00242857.
When is the last frost in Fairfield?
In Fairfield, the last spring frost (32°F) comes after May 13 in half of years and after June 1 in one year in ten; the first autumn frost comes before September 27 in half of years and before September 14 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 131 year in 10 after June 1; 9 in 10 after April 28
- First autumn frost, half of years before
- September 271 year in 10 before September 14; 9 in 10 before October 9
NOAA puts the median frost-free season at 135 days, and the season without a hard freeze (28°F) at 160 days.
A hard freeze (28°F) comes after April 30 in half of springs and before October 7 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Fairfield in zone 4b in ZIP code 59436, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Fairfield's NOAA station is in zone 4b: the coldest night of a typical year reaches −20°F (21 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 USC00242857; 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 Fairfield?
In a normal year in Fairfield, 8 days a year reach 90°F, 160 nights fall to 32°F or colder and 69 days bring measurable precipitation.
- Days at 90°F or more
- 8a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 160a normal year
- Days that stay below freezing
- 41high of 32°F or less
- Days with 0.01 inch of precipitation
- 69a normal year
The highest temperature in this station's record (since 1927) is 103°F, on August 24, 1969; the lowest is −44°F, on February 15, 1936.
The wettest calendar year on that record is 1975, with 26.30 in; the snowiest season is 1985–86, with 78.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00242857; records: ACIS (NOAA Regional Climate Centers), station USC00242857. Records use complete months only; a month missing more than three days is left out.
How sunny is Fairfield?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Fairfield, 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 Fairfield need?
A normal year in Fairfield brings 7,742 heating degree days, 44% more than the median U.S. place (5,373), and 256 cooling degree days, 72% 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 1,732 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,206 | 0 |
| February | 1,071 | 0 |
| March | 950 | 0 |
| April | 686 | 0 |
| May | 424 | 5 |
| June | 213 | 20 |
| July | 63 | 109 |
| August | 83 | 97 |
| September | 285 | 22 |
| October | 634 | 2 |
| November | 936 | 0 |
| December | 1,190 | 0 |
| Year (annual) | 7,742 | 256 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00242857. 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 Fairfield been warmer than normal lately?
2022 averaged 43.8°F, 0.6°F below the 1991-2020 normal of 44.4°F.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 43.8°F | −0.6°F | 8.75 |
Over 78 complete years from 1927 to 2024, the station's annual mean temperature rose at a fitted 1.9°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00242857; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Fairfield's climate compare?
Fairfield is warmer than 80 of the other 140 places with their own NOAA record in Montana, and wetter than 21. Across the 7,247 U.S. stations with normals, its annual mean of 44.4°F is warmer than 17%.
In the Köppen classification computed from these normals, Fairfield 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 Fairfield share this climate record?
3 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.
- Simms, MT326 people · 9 mi S
- Dutton, MT314 people · 20 mi NE
- Power, MT194 people · 15 mi NE
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 Fairfield's climate
What is the coldest month in Fairfield?
January, with a normal high of 36°F and a normal low of 17°F. The warmest is July (80°F by day, 53°F at night).
Does it snow in Fairfield?
Yes. NOAA publishes no 1991-2020 snowfall normal for Fairfield's NOAA station; the nearest record that keeps one, Choteau (17 miles away), records 48 inches of snow in a normal year.
What is the rainiest month in Fairfield?
June, with 2.63 in of precipitation in a normal year; the driest is December with 0.33 in.
What plant hardiness zone is Fairfield in?
The USDA's 2023 map puts Fairfield in zone 4b in ZIP code 59436, the nearest ZIP area. By the same method at Fairfield's NOAA station, the coldest night of a typical year reaches −20°F (21 years, 1991-2020): zone 4b.
How late can frost come in Fairfield?
In half of years the last 32°F night comes after May 13; in one year in ten it comes after June 1. Waiting until June 1 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Sun River (4 mi S), MT15 miles from this station, 43.6°F a year
- Choteau, MT17 miles from this station, 43.8°F a year
- Augusta, MT21 miles from this station, 45.4°F a year
- Bynum, MT25 miles from this station, 43.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made