Temperature
Hot by day, brisk at night.
87°Ftypical September high
Typical range
September climate
September in Calistoga / Napa Valley
United States · North America
Hot days and plenty of sun.
Good overall
Daytime high
87°F
Lows around 59°F
Rain
Very little rain
Sun
12 h/day
Air feel
Comfortable
When to visit
Month-by-month fit
Best
Precipitation
Mostly dry. About 1 wet day, fewer than in most months.
3%wet-day frequency
AmountWet-day chance
Sunshine
Plenty of sun this month.
11.9 hSeptember sunshine
Heat & humidity by month
Warm days with mostly dry air.
LowSeptember Heat feel
Easy airWarm airHot airHumid air
Hourly temperature pattern
In September, afternoons feel about 82° and nights feel near 59°.
Very coldColdCoolComfortableWarmHotNight hours
Clear sky
Clear skies this month.
83%September Clear sky
Clear skyCloud
Wind pattern
Calm winds are typical in September.
4 mphSeptember Calm
More detailIncludes daypart comfort
Typical September day
September late afternoons are around 85°F, easing to about 75°F in early evening.
Avg temp Typical range
Morning70°F
Rain2%
Cloud21%
Humid airLow
Sun intensityModerate
Midday81°F
Rain2%
Cloud16%
Humid airLow
Sun intensityStrong
Late afternoon85°F
Rain2%
Cloud16%
Humid airLow
Sun intensityStrong
Early evening75°F
Rain1%
Cloud13%
Humid airLow
Sun intensityMinimal
Best windowData tableView month-by-month numbers
View month-by-month numbers
| Month | High°F | Low°F | Rainin | Wet days | Sunh | Humidity% |
|---|---|---|---|---|---|---|
| Jan | 60 | 43 | 5.0 | 9 | 6.7 | 77 |
| Feb | 63 | 44 | 5.4 | 10 | 8.0 | 73 |
| Mar | 67 | 46 | 3.7 | 9 | 9.4 | 70 |
| Apr | 72 | 49 | 1.6 | 5 | 11.3 | 64 |
| May | 79 | 54 | 0.9 | 3 | 12.8 | 59 |
| Jun | 86 | 59 | 0.2 | 1 | 13.6 | 54 |
| Jul | 90 | 61 | 0.0 | 0 | 13.9 | 56 |
| Aug | 89 | 61 | 0.0 | 0 | 13.0 | 58 |
| Sep | 87 | 59 | 0.2 | 1 | 11.9 | 57 |
| Oct | 79 | 54 | 1.4 | 3 | 9.9 | 59 |
| Nov | 67 | 47 | 3.0 | 7 | 8.1 | 71 |
| Dec | 59 | 43 | 5.6 | 10 | 6.5 | 76 |
Similar climates
Similar
Similar travel styleLos OlivosUnited StatesSimilar travel styleMontecitoUnited StatesSimilar travel styleSan Miguel de AllendeMexicoSimilar travel styleLaguna BeachUnited States
Want a side-by-side climate view? Compare Calistoga / Napa Valley with Los Olivos.
Climate data notePlanning guidance, not a forecast
Typical monthly values are based on long-term climate records. Useful for planning, not a forecast. Check the weather before you travel.
Sunshine: source type is not yet identified at metric level.
Local microclimates can vary by beach, neighborhood, trail, or elevation.
Last updated: Jun 1, 2026
Data & methodology