Photo: Montanabw · CC BY-SA 3.0Precipitation in Great Falls trails that of 94% of U.S. towns: 13 inches a year
The coldest hours of a January night bottom out at 13° on average. Its January nights bite harder than in 89% of U.S. towns. Warming shows here too: 1.4° more than in 1901–2000, led by January. Seedlings are safe outdoors from about May 19, with the first autumn frost due around September 24.
A year in Great Falls at a glance
Each month’s typical high and low, and what it brings.
What stands out about Great Falls’ climate
Compared with towns across the U.S., with Great Falls’ place in Montana beside it.
What a year in Great Falls feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 126 frost-free days a year
In half of years the last 32° night comes by May 19 and the first by September 24. Frost and day counts come from NOAA’s station at Great Falls International Airport, 4 miles from the city’s center point, 240 ft higher.
The 2023 USDA map puts Great Falls’ center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −24°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 66 inches of snow a winter
Snow, measured at Great Falls International Airport, falls mostly in January, February, March, April, November and December. Precipitation (rain plus melted snow) adds up to 13 inches a year; June is the wettest month and December the driest. Rain or snow falls on about 98 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Great Falls
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Great Falls International Airport.
Living with Great Falls’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
126 frost-free days in zone 4b. The last frost comes by May 19 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 24.
Months with highs of 62–84° and lows of 40° or more: June, August and September. 13 miles of trails are waiting.
Parks & trails →Cold waves are 47% of the yearly building losses FEMA expects in Great Falls from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Great Falls and its neighbors
Every town next door is within a degree of Great Falls in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Great Falls’, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Great Falls, MT | 13° | 84° | 13" | 66" |
| Rexburg, ID | 12° | 84° | 13" | 70" |
| Cheyenne, WY | 16° | 85° | 15" | 65" |
| Durango, CO | 12° | 86° | 18" | 64" |
| Doney Park, AZ | 17° | 86° | 16" | 52" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Great Falls averaged 1.4° warmer than the 1900s. The biggest change is in January (+5.0°).
A bigger shift than in 52% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Great Falls compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Great Falls’ place among Montana’s.
Great Falls weather by month
Highs, lows and precipitation from NOAA’s grid at Great Falls’ center; snow, wet days and snow on the ground from Great Falls International Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 35° | 13° | 0.5" | 9.2" | 7 | 14 | 12° – 36° |
| February | 38° | 14° | 0.5" | 10.1" | 8 | 11 | −1° – 38° |
| March | 47° | 22° | 0.6" | 10.1" | 8 | 8 | 17° – 43° |
| April | 56° | 30° | 1.5" | 9.4" | 10 | 3 | 37° – 48° |
| May | 66° | 39° | 2.3" | 1.9" | 11 | 1 | 48° – 58° |
| June | 74° | 46° | 2.7" | 0.3" | 12 | 0 | 56° – 66° |
| July | 84° | 52° | 1.1" | 0.0" | 7 | 0 | 58° – 77° |
| August | 84° | 50° | 1.1" | 0.3" | 7 | 0 | 61° – 71° |
| September | 73° | 43° | 1.3" | 0.8" | 7 | 0 | 53° – 64° |
| October | 58° | 32° | 0.9" | 5.2" | 7 | 3 | 36° – 52° |
| November | 44° | 23° | 0.6" | 9.2" | 7 | 8 | 21° – 43° |
| December | 36° | 16° | 0.4" | 9.6" | 7 | 11 | 14° – 35° |
| Year | 58° | 32° | 13.4" | 66.1" | 98 | 60 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from -1° to 38°. June is the most reliable, staying within 10°.
Where Great Falls’ numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Great Falls’ center.
- Snow: Great Falls International Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Great Falls International Airport, 4 miles from the city’s center point, 240 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Great Falls’ climate
What is the weather like in Great Falls?
A typical July afternoon reaches 84°, a January night drops to 13°, and about 66 inches of snow falls in a normal winter. Colder January nights than 89% of U.S. towns; cooler July afternoons than 56% of U.S. towns.
How cold does it get in Great Falls in winter?
January nights average 13°. About 168 nights a year reach 32° or below and 21 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Great Falls get?
About 66 inches in a normal winter at Great Falls International Airport, most of it in January, February, March, April, November and December, with snow on the ground about 60 days a year.
How hot does it get in Great Falls?
July, with a typical high of 84° and a low of 52°. About 22 days a year reach 90° (Great Falls International Airport).
When is the first and last frost in Great Falls?
In half of years the last spring frost (32°) comes by May 19 and the first fall frost by September 24, about 126 frost-free days, at Great Falls International Airport.
What growing zone is Great Falls in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −24°.
What is the best time of year to visit Great Falls?
By one simple rule (highs of 62–84° and lows of 40° or more), June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Great Falls getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 52% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Great Falls.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.