Big Rainbow Lake Weather Forecast
- 34
- 53
Sunny
- 36
- 57
Sunny
- 38
- 59
Mostly Sunny
- 39
- 59
Mostly Cloudy
- 36
- 56
Mostly Sunny
- 33
- 51
Mostly Sunny
- 37
- 55
Mostly Sunny
Today 16 Sep Boise Mountains
Widespread fog this morning. Sunny. Highs 66 to 79.
Tonight 16 Sep Boise Mountains
Mostly clear. Patchy fog after midnight. Lows 36 to 51.
Big Rainbow Lake Temperature Statistics
September Temperature
Boise Air Terminal (41 miles)
Lowest 12 September, 2025
55 °FAverage September
73.8 °FHighest 1 September, 2025
100 °F
Climate (2020–Present)
Boise Air Terminal (41 miles)
Average Low 2020–2025
43.8 °FAverage 2020–2025
54.5 °FAverage High 2020–2025
65.8 °F