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The temperatures in Great Falls in May are quite cold with temperatures between 5°C and 17°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Great Falls during the month of May. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Please note that Great Falls can expect a few days of snow in May.
Our weather forecast can give you a great sense of what weather to expect in Great Falls in May 2025.
If you’re planning to visit Great Falls in the near future, we highly recommend that you review the 14 day weather forecast for Great Falls before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 0° / -7° | 3 | 16 | 12 | 19 mm | Awful | Great Falls in January |
| February | 0° / -8° | 3 | 11 | 15 | 23 mm | Awful | Great Falls in February |
| March | 7° / -3° | 3 | 17 | 11 | 25 mm | Bad | Great Falls in March |
| April | 11° / 1° | 4 | 19 | 7 | 46 mm | Bad | Great Falls in April |
| May | 17° / 5° | 5 | 24 | 2 | 53 mm | Ok | Great Falls in May |
| June | 23° / 9° | 4 | 26 | 0 | 49 mm | Perfect | Great Falls in June |
| July | 29° / 14° | 1 | 30 | 0 | 16 mm | Good | Great Falls in July |
| August | 28° / 14° | 1 | 30 | 0 | 27 mm | Perfect | Great Falls in August |
| September | 23° / 10° | 2 | 28 | 1 | 20 mm | Perfect | Great Falls in September |
| October | 13° / 3° | 3 | 24 | 4 | 30 mm | Bad | Great Falls in October |
| November | 6° / -2° | 3 | 19 | 9 | 20 mm | Awful | Great Falls in November |
| December | -1° / -8° | 2 | 15 | 13 | 18 mm | Awful | Great Falls in December |