Flatwillow (4 mi ENE), Montana climate: Climate normals at a NOAA weather station
Flatwillow (4 mi ENE)'s normal year runs from 14°F January nights to 86°F July afternoons, with 14.2 inches of precipitation and 43 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.1°C, January lows of −10°C, July highs of 30°C, 360 mm of precipitation a year.
- NOAA stationFlatwillow (4 mi ENE)
- Station IDUSC00243013
- Location46.82°N 108.37°W
- Elevation3,292 ft (1,003 m)
On October 22, the normal high in Flatwillow (4 mi ENE) is 57°F and the normal low 33°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 Flatwillow (4 mi ENE).
- Jan 36° 14°
- Feb 38° 16°
- Mar 48° 24°
- Apr 58° 32°
- May 67° 41°
- Jun 76° 50°
- Jul 86° 55°
- Aug 86° 54°
- Sep 75° 45°
- Oct 60° 35°
- Nov 46° 24°
- Dec 37° 16°
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 Flatwillow (4 mi ENE) each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 14°F. The most precipitation falls in May (2.83 in), the least in February (0.45 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 36°F | 14°F | 25.0°F | 0.48 | 10.4 | 4 | <1 | 29 | 9 h |
| February | 38°F | 16°F | 27.2°F | 0.45 | 9.0 | 4 | <1 | 26 | 10 h 20 min |
| March | 48°F | 24°F | 36.3°F | 0.58 | 4.7 | 6 | <1 | 25 | 11 h 50 min |
| April | 58°F | 32°F | 44.8°F | 1.41 | 4.2 | 7 | <1 | 18 | 13 h 30 min |
| May | 67°F | 41°F | 53.9°F | 2.83 | 0.2 | 9 | 1 | 6 | 15 h |
| June | 76°F | 50°F | 62.7°F | 2.72 | 0.0 | 9 | 3 | <1 | 15 h 50 min |
| July | 86°F | 55°F | 70.4°F | 1.27 | 0.0 | 6 | 14 | <1 | 15 h 30 min |
| August | 86°F | 54°F | 69.6°F | 1.14 | 0.0 | 5 | 14 | <1 | 14 h 20 min |
| September | 75°F | 45°F | 59.8°F | 1.17 | 0.0 | 5 | 4 | 2 | 12 h 40 min |
| October | 60°F | 35°F | 47.2°F | 1.16 | 2.3 | 5 | <1 | 14 | 11 h |
| November | 46°F | 24°F | 35.0°F | 0.50 | 3.8 | 4 | <1 | 24 | 9 h 30 min |
| December | 37°F | 16°F | 26.2°F | 0.48 | 8.8 | 4 | <1 | 29 | 8 h 30 min |
| Year (annual) | 59°F | 34°F | 46.5°F | 14.19 | 43.4 | 70 | 35 | 173 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 2°C | −10°C | −3.9°C | 12 mm | 26 cm |
| February | 3°C | −9°C | −2.7°C | 11 mm | 23 cm |
| March | 9°C | −4°C | 2.4°C | 15 mm | 12 cm |
| April | 14°C | 0°C | 7.1°C | 36 mm | 11 cm |
| May | 19°C | 5°C | 12.2°C | 72 mm | 1 cm |
| June | 24°C | 10°C | 17.1°C | 69 mm | 0 cm |
| July | 30°C | 13°C | 21.3°C | 32 mm | 0 cm |
| August | 30°C | 12°C | 20.9°C | 29 mm | 0 cm |
| September | 24°C | 7°C | 15.4°C | 30 mm | 0 cm |
| October | 15°C | 2°C | 8.4°C | 29 mm | 6 cm |
| November | 8°C | −5°C | 1.7°C | 13 mm | 10 cm |
| December | 3°C | −9°C | −3.2°C | 12 mm | 22 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00243013; 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 Flatwillow (4 mi ENE)?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (5).
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 USC00243013.
When is the last frost at Flatwillow (4 mi ENE)?
In Flatwillow (4 mi ENE), the last spring frost (32°F) comes after May 16 in half of years and after May 31 in one year in ten; the first autumn frost comes before September 28 in half of years and before September 15 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 May 31; 9 in 10 after May 3
- First autumn frost, half of years before
- September 281 year in 10 before September 15; 9 in 10 before October 10
NOAA puts the median frost-free season at 132 days, and the season without a hard freeze (28°F) at 153 days.
A hard freeze (28°F) comes after May 3 in half of springs and before October 5 in half of autumns.
By the USDA's method, the average of each year's coldest night over 1991-2020, the station is in plant hardiness zone 4b: the coldest night of a typical year reaches −24°F (25 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 USC00243013; 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 Flatwillow (4 mi ENE)?
In a normal year in Flatwillow (4 mi ENE), 35 days a year reach 90°F (3 of them 100°F or more), 173 nights fall to 32°F or colder and 70 days bring measurable precipitation.
- Days at 90°F or more
- 35a 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
- 34high of 32°F or less
- Days with 0.01 inch of precipitation
- 70a normal year
- Days with 1 inch of snow or more
- 14a normal year
The highest temperature in this station's record (since 1913) is 111°F, on July 12, 2026; the lowest is −46°F, on February 17, 1936.
The wettest calendar year on that record is 2018, with 22.88 in; the snowiest season is 2017–18, with 110.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00243013; records: ACIS (NOAA Regional Climate Centers), station USC00243013. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Flatwillow (4 mi ENE)?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds at Flatwillow (4 mi ENE), 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 | 72% | 1.7 |
| February | 74% | 2.6 |
| March | 71% | 3.7 |
| April | 68% | 4.8 |
| May | 71% | 5.8 |
| June | 77% | 6.7 |
| July | 87% | 7.1 |
| August | 85% | 5.9 |
| September | 79% | 4.4 |
| October | 73% | 2.8 |
| November | 71% | 1.8 |
| December | 66% | 1.3 |
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 Flatwillow (4 mi ENE) record?
A normal year at Flatwillow (4 mi ENE) brings 7,169 heating degree days, 33% more than the median U.S. place (5,373), and 460 cooling degree days, 49% 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 2,253 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,242 | 0 |
| February | 1,060 | 0 |
| March | 888 | 0 |
| April | 606 | 0 |
| May | 350 | 6 |
| June | 118 | 47 |
| July | 22 | 191 |
| August | 32 | 175 |
| September | 196 | 39 |
| October | 554 | 2 |
| November | 900 | 0 |
| December | 1,201 | 0 |
| Year (annual) | 7,169 | 460 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00243013. 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 Flatwillow (4 mi ENE) been warmer than normal?
2025 averaged 47.5°F, 1.0°F above the 1991-2020 normal of 46.5°F. 2 of the 3 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 45.7°F | −0.8°F | 14.93 | 49.2 |
| 2024 | 48.0°F | +1.5°F | 15.58 | 40.0 |
| 2025 | 47.5°F | +1.0°F | 15.38 | 71.7 |
Over 88 complete years from 1914 to 2025, the station's annual mean temperature rose at a fitted 2.7°F per century (+0.15°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00243013; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Flatwillow (4 mi ENE)'s climate compare?
Flatwillow (4 mi ENE) is warmer than 121 of the 141 places with their own NOAA record in Montana, and wetter than 51. Across the 7,247 U.S. stations with normals, its annual mean of 46.5°F is warmer than 25%.
In the Köppen classification computed from these normals, Flatwillow (4 mi ENE) 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 Flatwillow (4 mi ENE) share this climate record?
2 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.
- Winnett, MT197 people · 13 mi N
- Flat Willow Colony, MT0 people · 9 mi SW
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 Flatwillow (4 mi ENE)'s climate
What is the coldest month at Flatwillow (4 mi ENE)?
January, with a normal high of 36°F and a normal low of 14°F. The warmest is July (86°F by day, 55°F at night).
Does it snow at Flatwillow (4 mi ENE)?
Yes: 43 inches in a normal year, falling on 16 days with 0.1 inch or more, the most in January (10.4 inches).
What is the rainiest month at Flatwillow (4 mi ENE)?
May, with 2.83 in of precipitation in a normal year; the driest is February with 0.45 in.
What plant hardiness zone is Flatwillow (4 mi ENE) in?
By the same method at the station, the coldest night of a typical year reaches −24°F (25 years, 1991-2020): zone 4b.
How late can frost come at Flatwillow (4 mi ENE)?
In half of years the last 32°F night comes after May 16; in one year in ten it comes after May 31. Waiting until May 31 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Grass Range, MT25 miles from this station, 45.5°F a year
- Roundup, MT27 miles from this station, 46.5°F a year
- Melstone, MT28 miles from this station, 47.2°F a year
- Mosby (4 mi ENE), MT29 miles from this station, 48.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made