Click on a day for an hourly weather forecast
The temperatures in Helena in August are comfortable with low of 10°C and and high up to 26°C.
You can expect about 3 to 8 days of rain in Helena during the month of August. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Helena in August 2025.
If you’re planning to visit Helena in the near future, we highly recommend that you review the 14 day weather forecast for Helena before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -9° | 6 | 10 | 16 | 39 mm | Awful | Helena in January |
| February | -2° / -10° | 6 | 5 | 18 | 47 mm | Awful | Helena in February |
| March | 4° / -5° | 8 | 10 | 15 | 62 mm | Awful | Helena in March |
| April | 9° / -3° | 8 | 10 | 12 | 86 mm | Awful | Helena in April |
| May | 15° / 2° | 9 | 19 | 3 | 106 mm | Bad | Helena in May |
| June | 21° / 6° | 8 | 22 | 0 | 105 mm | Ok | Helena in June |
| July | 28° / 9° | 3 | 28 | 0 | 45 mm | Perfect | Helena in July |
| August | 26° / 10° | 3 | 28 | 0 | 49 mm | Perfect | Helena in August |
| September | 21° / 6° | 3 | 26 | 1 | 44 mm | Good | Helena in September |
| October | 11° / 0° | 4 | 22 | 6 | 51 mm | Bad | Helena in October |
| November | 3° / -6° | 3 | 15 | 12 | 38 mm | Awful | Helena in November |
| December | -3° / -10° | 6 | 8 | 17 | 37 mm | Awful | Helena in December |