Climate Insights for Helena

The climate in Helena is cool. The average annual temperature is 6°C and approximately 516mm of precipitation falls per year. October is the wettest month, receiving around 81mm of rainfall. Helena is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are December, January, February, when temperatures can drop to -14°C. Snowfall occurs from January to December, with around 150cm accumulating over the season.

Helena has a wide annual temperature range, spanning 41°C from the coldest to warmest months. The warmest month is July, when average highs reach 27°C and the mean temperature sits around 18°C. The coldest month is December, when overnight lows fall to -14°C and the daily average is -10°C. On average, daily temperatures fluctuate by about 12°C between overnight lows and afternoon highs. The sharpest temperature change occurs between November and December, with a 14°C shift in average temperatures.

Helena is a relatively dry area, receiving approximately 516mm of precipitation annually, which averages out to around 43mm per month. The wettest month is October, averaging 81mm of rainfall. May and April also tend to see above-average precipitation. The driest month is February, with just 14mm. That's 67mm less than October, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Snowfall is a regular feature from January to December, with around 150cm accumulating over the season. December typically sees the most snow at around 45cm.

Helena is relatively calm, with an average annual wind speed of 3km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 3km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 2km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 1km/h gap between the calmest and windiest months.

It is currently summer in Helena, which began on June 21, 2026. Helena is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 27°C, while the coldest stretch bottoms out in December near -14°C. Autumn is next, beginning on September 23, 2026 — 52 days from now.

The best time to visit Helena is during June, July and August, when the weather is most comfortable for travellers. During these months, average temperatures hover around 17°C with modest rainfall averaging 37mm per month. By contrast, December can be quite cold with temperatures dropping to -14°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Helena based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.