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Great Falls, Montana climate
Cfb Oceanic / temperate
Great Falls has a seasonal cool-temperate climate (Oceanic / temperate, Köppen Cfb). The hottest month is July with an average daily high near 30°C, while the coldest is January averaging around −8°C at night. Precipitation totals about 392 mm a year and is strongly seasonal — June alone averages 70 mm while December barely receives 14 mm.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsGreat Falls climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 3 | 4 | 9 | 15 | 19 | 24 | 30 | 29 | 23 | 15 | 7 | 3 |
| Avg temp (°C) | −3 | −2 | 3 | 8 | 12 | 17 | 21 | 20 | 15 | 9 | 2 | −2 |
| Avg low (°C) | −8 | −7 | −4 | 1 | 6 | 10 | 13 | 12 | 7 | 2 | −3 | −7 |
| Precipitation (mm) | 15 | 15 | 16 | 45 | 68 | 70 | 34 | 33 | 35 | 29 | 18 | 14 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 3 | 4 | 9 | 15 | 19 | 24 |
| Avg temp (°C) | −3 | −2 | 3 | 8 | 12 | 17 |
| Avg low (°C) | −8 | −7 | −4 | 1 | 6 | 10 |
| Precipitation (mm) | 15 | 15 | 16 | 45 | 68 | 70 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 30 | 29 | 23 | 15 | 7 | 3 |
| Avg temp (°C) | 21 | 20 | 15 | 9 | 2 | −2 |
| Avg low (°C) | 13 | 12 | 7 | 2 | −3 | −7 |
| Precipitation (mm) | 34 | 33 | 35 | 29 | 18 | 14 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 6 | 8 | 6 | 9 | 11 | 9 | 6 | 5 | 7 | 6 | 6 | 6 |
| Days with high ≥ 32°C (days) | — | — | — | — | 0.1 | 2 | 12 | 8 | 2 | — | — | — |
| Days with low ≤ 0°C (days) | 23 | 22 | 20 | 13 | 3 | 0.2 | — | — | 0.7 | 9 | 17 | 24 |
| Days with snowfall ≥ 2.5 cm (days) | 3 | 3 | 2 | 2 | 0.3 | 0.1 | — | — | 0.1 | 0.8 | 2 | 3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 6 | 8 | 6 | 9 | 11 | 9 |
| Days with high ≥ 32°C (days) | — | — | — | — | 0.1 | 2 |
| Days with low ≤ 0°C (days) | 23 | 22 | 20 | 13 | 3 | 0.2 |
| Days with snowfall ≥ 2.5 cm (days) | 3 | 3 | 2 | 2 | 0.3 | 0.1 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 6 | 5 | 7 | 6 | 6 | 6 |
| Days with high ≥ 32°C (days) | 12 | 8 | 2 | — | — | — |
| Days with low ≤ 0°C (days) | — | — | 0.7 | 9 | 17 | 24 |
| Days with snowfall ≥ 2.5 cm (days) | — | — | 0.1 | 0.8 | 2 | 3 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 71 | 69 | 70 | 70 | 67 | 61 | 43 | 47 | 53 | 65 | 70 | 68 |
| Clear days (≤ 30% cloud) | 2 | 3 | 3 | 3 | 4 | 5 | 12 | 11 | 9 | 5 | 3 | 3 |
| Partly cloudy days (30–70%) | 11 | 9 | 10 | 10 | 11 | 12 | 12 | 13 | 9 | 10 | 10 | 11 |
| Cloudy days (≥ 70%) | 18 | 16 | 18 | 18 | 17 | 13 | 7 | 8 | 12 | 16 | 17 | 17 |
| Relative humidity (%) | 80 | 75 | 68 | 62 | 59 | 58 | 50 | 49 | 55 | 63 | 72 | 77 |
| Wind speed (km/h) | 12.6 | 11.7 | 11.2 | 10.2 | 9.0 | 8.6 | 7.5 | 7.3 | 8.5 | 10.3 | 11.7 | 12.3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 71 | 69 | 70 | 70 | 67 | 61 |
| Clear days (≤ 30% cloud) | 2 | 3 | 3 | 3 | 4 | 5 |
| Partly cloudy days (30–70%) | 11 | 9 | 10 | 10 | 11 | 12 |
| Cloudy days (≥ 70%) | 18 | 16 | 18 | 18 | 17 | 13 |
| Relative humidity (%) | 80 | 75 | 68 | 62 | 59 | 58 |
| Wind speed (km/h) | 12.6 | 11.7 | 11.2 | 10.2 | 9.0 | 8.6 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 43 | 47 | 53 | 65 | 70 | 68 |
| Clear days (≤ 30% cloud) | 12 | 11 | 9 | 5 | 3 | 3 |
| Partly cloudy days (30–70%) | 12 | 13 | 9 | 10 | 10 | 11 |
| Cloudy days (≥ 70%) | 7 | 8 | 12 | 16 | 17 | 17 |
| Relative humidity (%) | 50 | 49 | 55 | 63 | 72 | 77 |
| Wind speed (km/h) | 7.5 | 7.3 | 8.5 | 10.3 | 11.7 | 12.3 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Great Falls 16st (NOAA GHCN station USC00243749), about 2 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.