Chessman Reservoir Weather Forecast
- 26
- 43
Decreasing Clouds
- 32
- 53
Chance Rain Showers
- 32
- 50
Rain Showers
- 32
- 54
Partly Sunny
- 36
- 59
Slight Chance Thunderstorms
- 41
- 67
Partly Sunny
- 42
- 71
Mostly Sunny
Today 18 May Upper Blackfoot and MacDonald Pass
Not as cool. Partly sunny. Chance of rain Showers and slight chance of snow Showers early in the Afternoon, then slight chance of rain Showers and snow Showers late in the afternoon. Highs 42 to 52. North Winds up to 10 Mph. Chance of precipitation 50 percent.
Tonight 18 May Upper Blackfoot and MacDonald Pass
Partly cloudy. Lows in the upper 20s. West Winds up to 10 Mph.
Chessman Reservoir Temperature Statistics
May Temperature
Helena Regional Airport (13 miles)
Lowest 6 May, 2026
27.6 °FAverage May
55.7 °FHighest 13 May, 2026
84.7 °F
Climate (2021–Present)
Helena Regional Airport (13 miles)
Average Low 2021–2026
36.5 °FAverage 2021–2026
48.1 °FAverage High 2021–2026
60.1 °F