South Mountain Reservoir Weather Forecast
- 37
- 60
Rain Showers
- 42
- 60
Rain Showers Likely
- 38
- 57
Rain Showers Likely
- 37
- 62
Partly Sunny
- 41
- 67
Mostly Sunny
- 45
- 74
Mostly Sunny
- 47
- 78
Partly Sunny
Today 27 May Modoc County
Rain Showers and slight chance of Thunderstorms late this Morning, then chance of Thunderstorms late this afternoon. Some Thunderstorms may produce gusty Winds, small Hail, and heavy Rainfall, then some Thunderstorms may be severe with gusty Winds, small Hail, and heavy rainfall late this afternoon. Highs in the mid 50s to lower 60s. North Winds 10 to 20 Mph. Chance of precipitation 90 percent.
Tonight 27 May Modoc County
Partly cloudy then becoming mostly clear in the late evening and early morning then becoming partly cloudy. A 10 percent chance of Thunderstorms early this evening. Some Thunderstorms may be severe with gusty Winds, small Hail, and heavy rainfall. Lows in the mid 30s to lower 40s. East Winds 5 to 10 Mph.
South Mountain Reservoir Temperature Statistics
May Temperature
Alturas (22.4 miles)
Lowest 19 May, 2026
27.6 °FAverage May
57.1 °FHighest 12 May, 2026
88.6 °F
Climate (2021–Present)
Alturas (22.4 miles)
Average Low 2021–2026
33.5 °FAverage 2021–2026
49.7 °FAverage High 2021–2026
65 °F