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The weather in Helena in May is very cold with temperatures between 2°C and 15°C, warm clothes are a must.
You can expect rain for roughly half of the month of May in Helena. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
You can expect a few days of snow in Helena during May. It’s important to get out your snow boots and warm mittens to stay warm while you explore Helena.
Our weather forecast can give you a great sense of what weather to expect in Helena in May 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 |