Petaluma River - Black John Slough Entrance Weather Forecast
- 57
- 91
Sunny
- 57
- 92
Sunny
- 59
- 91
Mostly Sunny
- 60
- 81
Chance Rain Showers
- 58
- 81
Slight Chance Rain Showers
- 58
- 81
Mostly Sunny
- 57
- 82
Mostly Sunny
Today 15 Sep North Bay Interior Valleys
Sunny. Highs in the 80s to 90s. South Winds 5 to 10 Mph.
Tonight 15 Sep North Bay Interior Valleys
Clear. Lows in the lower 50s to mid 60s. West Winds 5 to 10 Mph.
Petaluma River - Black John Slough Entrance Temperature Statistics
September Temperature
Novato / Gnoss Field (1.9 miles)
Lowest 1 September, 2025
51.8 °FAverage September
66.1 °FHighest 1 September, 2025
89.6 °F
Climate (2020–Present)
Novato / Gnoss Field (1.9 miles)
Average Low 2020–2025
46 °FAverage 2020–2025
57.5 °FAverage High 2020–2025
72.6 °F