Cornerstone Weather Forecast
- 53
- 78
Mostly Sunny
- 54
- 83
Partly Sunny
- 50
- 75
Mostly Cloudy
- 49
- 67
Chance Rain
- 48
- 66
Chance Rain
- 46
- 66
Sunny
- 48
- 73
Sunny
Today 28 Mar Carquinez Strait and Delta
Sunny. Highs 77 to 83. Light Winds.
Tonight 28 Mar Carquinez Strait and Delta
Mostly clear. Lows 50 to 56. West Winds up to 10 Mph.
Cornerstone Temperature Statistics
March Temperature
Napa, Napa County Airport (7.5 miles)
Lowest 5 March, 2026
37.7 °FAverage March
60.3 °FHighest 20 March, 2026
87.7 °F
Climate (2021–Present)
Napa, Napa County Airport (7.5 miles)
Average Low 2021–2026
47.2 °FAverage 2021–2026
58.3 °FAverage High 2021–2026
70.2 °F