Climate averages 1991–2020
Vacaville weather
in August.
A hot, very dry month: the 2nd warmest and the 2nd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a hot month in Vacaville: daytime highs average 32.0°C and nights cool to about 15.7°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 1.0 mm of rain on fewer than one day, which makes August a very dry month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 39 min on an average August day.
The nearest other city in this atlas is Fairfield (13 km away). In August its highs average 29.8°C, 2.2°C cooler than Vacaville, with 1.0 mm of rain.
Among the 498 cities listed in the United States, Vacaville ranks joint 134th of 498 for the warmest August highs and joint 51st of 498 for the driest August (rainfall, lowest first). The mean August high of those 498 cities is 29.9°C; Vacaville is 2.1°C warmer than that mean.
From August to September, average highs fall by 1.6°C to 30.4°C, and monthly rainfall rises from 1.0 mm to 1.5 mm.
The annual picture
August 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
Vacaville climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 14.0°C5.4°C | 5.4°C | 109 | 9.2 | 9.810 h |
| February | 15.8°C6.4°C | 6.4°C | 108 | 9.1 | 10.711 h |
| March | 18.2°C7.7°C | 7.7°C | 79 | 8.2 | 11.912 h |
| April | 21.3°C9.4°C | 9.4°C | 34 | 4.8 | 13.213 h |
| May | 25.8°C12.2°C | 12.2°C | 18 | 3.2 | 14.214 h |
| June | 30.4°C14.8°C | 14.8°C | 4.2 | 0.9 | 14.815 h |
| July | 32.4°C15.7°C | 15.7°C | 0.4 | 0.1 | 14.615 h |
| August, selected | 32.0°C15.7°C | 15.7°C | 1.0 | 0.2 | 13.714 h |
| September | 30.4°C15.3°C | 15.3°C | 1.5 | 0.4 | 12.512 h |
| October | 25.2°C12.9°C | 12.9°C | 24 | 2.7 | 11.211 h |
| November | 18.1°C8.6°C | 8.6°C | 50 | 5.8 | 10.110 h |
| December | 13.8°C5.8°C | 5.8°C | 101 | 9.0 | 9.510 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
August in nearby cities
- Fairfield in AugustUnited States · 13 kmHigh 29.8°C · Low 14.6°C · 1.0 mm rain
- Napa in AugustUnited States · 27 kmHigh 30.6°C · Low 14.9°C · 0.7 mm rain
- Vallejo in AugustUnited States · 37 kmHigh 28.6°C · Low 13.8°C · 0.9 mm rain
- Antioch in AugustUnited States · 42 kmHigh 30.0°C · Low 15.4°C · 1.5 mm rain
- Concord (California), United States in AugustUnited States · 42 kmHigh 28.8°C · Low 14.5°C · 1.5 mm rain
- Sacramento in AugustUnited States · 50 kmHigh 33.3°C · Low 16.3°C · 1.3 mm rain
- Elk Grove in AugustUnited States · 54 kmHigh 32.1°C · Low 15.7°C · 1.4 mm rain
- Berkeley in AugustUnited States · 59 kmHigh 26.2°C · Low 13.6°C · 0.9 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 Vacaville) is explained once on the Vacaville year overview and on the Sources, method and limits page.
Fairfield lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.