Climate averages 1991–2020
Napa weather
in April.
A mild, fairly dry month: the 7th warmest and the 7th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
April is a mild month in Napa: daytime highs average 20.7°C and nights cool to about 9.0°C. By daytime temperature it is the 7th warmest of the 12 months.
Expect about 38 mm of rain on roughly 5 days, which makes April a fairly dry month (the 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 10 min on an average April day.
The nearest other city in this atlas is Vallejo (22 km away). In April its highs average 20.3°C, about as warm as Napa, with 37 mm of rain.
Among the 498 cities listed in the United States, Napa ranks joint 221st of 498 for the warmest April highs and 119th of 498 for the driest April (rainfall, lowest first). The mean April high of those 498 cities is 19.4°C; Napa is 1.3°C warmer than that mean.
From April to May, average highs rise by 3.9°C to 24.6°C, and monthly rainfall falls from 38 mm to 20 mm.
The annual picture
April in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Napa climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 14.4°C5.3°C | 5.3°C | 116 | 9.4 | 9.810 h |
| February | 15.9°C6.3°C | 6.3°C | 117 | 8.7 | 10.711 h |
| March | 18.0°C7.5°C | 7.5°C | 86 | 8.4 | 11.912 h |
| April, selected | 20.7°C9.0°C | 9.0°C | 38 | 4.9 | 13.213 h |
| May | 24.6°C11.5°C | 11.5°C | 20 | 3.2 | 14.214 h |
| June | 28.9°C13.9°C | 13.9°C | 4.7 | 0.9 | 14.815 h |
| July | 30.7°C14.7°C | 14.7°C | 0.4 | 0.1 | 14.515 h |
| August | 30.6°C14.9°C | 14.9°C | 0.7 | 0.2 | 13.714 h |
| September | 29.5°C14.6°C | 14.6°C | 2.0 | 0.4 | 12.512 h |
| October | 25.1°C12.6°C | 12.6°C | 26 | 2.9 | 11.211 h |
| November | 18.3°C8.4°C | 8.4°C | 56 | 5.9 | 10.110 h |
| December | 14.2°C5.6°C | 5.6°C | 110 | 9.4 | 9.610 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
April in nearby cities
- Vallejo in AprilUnited States · 22 kmHigh 20.3°C · Low 8.5°C · 37 mm rain
- Fairfield in AprilUnited States · 22 kmHigh 20.7°C · Low 9.1°C · 34 mm rain
- Vacaville in AprilUnited States · 27 kmHigh 21.3°C · Low 9.4°C · 34 mm rain
- Santa Rosa, United States in AprilUnited States · 41 kmHigh 19.8°C · Low 7.8°C · 49 mm rain
- Concord (California), United States in AprilUnited States · 42 kmHigh 20.3°C · Low 9.1°C · 33 mm rain
- Berkeley in AprilUnited States · 47 kmHigh 18.9°C · Low 8.6°C · 34 mm rain
- Antioch in AprilUnited States · 53 kmHigh 20.9°C · Low 9.4°C · 31 mm rain
- Oakland in AprilUnited States · 55 kmHigh 18.9°C · Low 8.9°C · 34 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Napa) is explained once on the Napa year overview and on the Sources, method and limits page.