Great Falls 16ST, Montana climate: Climate normals at a NOAA weather station
Great Falls 16ST's normal year runs from 18°F January nights to 86°F July afternoons, with 15.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.3°C, January lows of −8°C, July highs of 30°C, 392 mm of precipitation a year.
- NOAA stationGreat Falls 16ST
- Station IDUSC00243749
- Location47.49°N 111.28°W
- Elevation3,505 ft (1,068 m)
On October 23, the normal high in Great Falls 16ST is 56°F and the normal low 34°F, and the chance of measurable rain or snow is 22%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Great Falls 16ST.
- Jan 37° 18°
- Feb 39° 19°
- Mar 48° 25°
- Apr 58° 33°
- May 67° 42°
- Jun 75° 50°
- Jul 86° 55°
- Aug 84° 53°
- Sep 73° 45°
- Oct 59° 36°
- Nov 45° 26°
- Dec 37° 20°
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 Great Falls 16ST each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 18°F. The most precipitation falls in June (2.74 in), the least in December (0.56 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 37°F | 18°F | 27.2°F | 0.61 | 6 | <1 | 24 | 8 h 50 min |
| February | 39°F | 19°F | 28.7°F | 0.58 | 9 | <1 | 24 | 10 h 10 min |
| March | 48°F | 25°F | 36.7°F | 0.63 | 6 | <1 | 22 | 11 h 50 min |
| April | 58°F | 33°F | 45.7°F | 1.79 | 9 | <1 | 14 | 13 h 30 min |
| May | 67°F | 42°F | 54.4°F | 2.66 | 11 | <1 | 3 | 15 h |
| June | 75°F | 50°F | 62.5°F | 2.74 | 9 | 2 | <1 | 16 h |
| July | 86°F | 55°F | 70.4°F | 1.34 | 6 | 13 | <1 | 15 h 40 min |
| August | 84°F | 53°F | 68.7°F | 1.30 | 6 | 8 | <1 | 14 h 20 min |
| September | 73°F | 45°F | 58.6°F | 1.39 | 7 | 2 | 1 | 12 h 40 min |
| October | 59°F | 36°F | 47.5°F | 1.13 | 7 | <1 | 11 | 11 h |
| November | 45°F | 26°F | 35.7°F | 0.70 | 6 | <1 | 19 | 9 h 20 min |
| December | 37°F | 20°F | 28.3°F | 0.56 | 7 | <1 | 26 | 8 h 30 min |
| Year (annual) | 59°F | 35°F | 47.0°F | 15.43 | 89 | 25 | 143 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −8°C | −2.7°C | 15 mm |
| February | 4°C | −7°C | −1.8°C | 15 mm |
| March | 9°C | −4°C | 2.6°C | 16 mm |
| April | 15°C | 1°C | 7.6°C | 45 mm |
| May | 19°C | 5°C | 12.4°C | 68 mm |
| June | 24°C | 10°C | 16.9°C | 70 mm |
| July | 30°C | 13°C | 21.3°C | 34 mm |
| August | 29°C | 12°C | 20.4°C | 33 mm |
| September | 23°C | 7°C | 14.8°C | 35 mm |
| October | 15°C | 2°C | 8.6°C | 29 mm |
| November | 7°C | −3°C | 2.1°C | 18 mm |
| December | 3°C | −7°C | −2.1°C | 14 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Great Falls (5 miles away), gets 66 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00243749; 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 Great Falls 16ST?
Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, August 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 USC00243749.
When is the last frost at Great Falls 16ST?
In Great Falls 16ST, the last spring frost (32°F) comes after May 6 in half of years and after May 19 in one year in ten; the first autumn frost comes before October 1 in half of years and before September 17 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 61 year in 10 after May 19; 9 in 10 after April 23
- First autumn frost, half of years before
- October 11 year in 10 before September 17; 9 in 10 before October 16
NOAA puts the median frost-free season at 147 days, and the season without a hard freeze (28°F) at 171 days.
A hard freeze (28°F) comes after April 24 in half of springs and before October 11 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Great Falls 16ST in zone 4b in ZIP code 59401, the nearest ZIP area.
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00243749; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Great Falls 16ST?
In a normal year in Great Falls 16ST, 25 days a year reach 90°F (1 of them 100°F or more), 143 nights fall to 32°F or colder and 89 days bring measurable precipitation.
- Days at 90°F or more
- 25a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 143a normal year
- Days that stay below freezing
- 39high of 32°F or less
- Days with 0.01 inch of precipitation
- 89a normal year
The highest temperature in this station's record (since 1891) is 107°F, on July 25, 1933; the lowest is −44°F, on January 10, 1909.
The wettest calendar year on that record is 1909, with 23.73 in; the snowiest season is 2017–18, with 93.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00243749; records: ACIS (NOAA Regional Climate Centers), station USC00243749. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Great Falls 16ST?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds at Great Falls 16ST, 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 Great Falls 16ST record?
A normal year at Great Falls 16ST brings 6,942 heating degree days, 29% more than the median U.S. place (5,373), and 422 cooling degree days, 54% 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 2,214 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,173 | 0 |
| February | 1,018 | 0 |
| March | 878 | 0 |
| April | 578 | 1 |
| May | 335 | 8 |
| June | 120 | 45 |
| July | 19 | 186 |
| August | 38 | 151 |
| September | 220 | 30 |
| October | 545 | 3 |
| November | 881 | 0 |
| December | 1,139 | 0 |
| Year (annual) | 6,942 | 422 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00243749. 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 Great Falls 16ST been warmer than normal?
2025 averaged 46.7°F, 0.3°F below the 1991-2020 normal of 47.0°F.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2025 | 46.7°F | −0.3°F | – |
Over 33 complete years from 1899 to 2025, the station's annual mean temperature rose at a fitted 1.7°F per century (+0.09°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00243749; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Great Falls 16ST's climate compare?
Great Falls 16ST is warmer than 128 of the 141 places with their own NOAA record in Montana, and wetter than 82. Across the 7,247 U.S. stations with normals, its annual mean of 47.0°F is warmer than 28%.
In the Köppen classification computed from these normals, Great Falls 16ST 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 Great Falls 16ST share this climate record?
8 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.
- Malmstrom AFB, MT4,191 people · 5 mi E
- Black Eagle, MT654 people · 3 mi N
- Gibson Flats, MT203 people · 2 mi SE
- Stockett, MT148 people · 11 mi SE
- Sand Coulee, MT146 people · 8 mi SE
- Tracy, MT130 people · 8 mi SE
- Big Stone Colony, MT44 people · 7 mi SE
- Centerville, MT11 people · 10 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 Great Falls 16ST's climate
What is the coldest month at Great Falls 16ST?
January, with a normal high of 37°F and a normal low of 18°F. The warmest is July (86°F by day, 55°F at night).
Does it snow at Great Falls 16ST?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Great Falls (5 miles away), records 66 inches of snow in a normal year.
What is the rainiest month at Great Falls 16ST?
June, with 2.74 in of precipitation in a normal year; the driest is December with 0.56 in.
What plant hardiness zone is Great Falls 16ST in?
The USDA's 2023 map puts Great Falls 16ST in zone 4b in ZIP code 59401, the nearest ZIP area.
How late can frost come at Great Falls 16ST?
In half of years the last 32°F night comes after May 6; in one year in ten it comes after May 19. Waiting until May 19 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Great Falls, MT5 miles from this station, 44.6°F a year
- Carter (14 mi W), MT21 miles from this station, 43.9°F a year
- Sun River (4 mi S), MT21 miles from this station, 43.6°F a year
- Cascade, MT27 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