Climate averages 1991–2020
Vacaville weather
in January.
A cool, wet month: the 11th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a cool month in Vacaville: daytime highs average 14.0°C and nights cool to about 5.4°C. By daytime temperature it is the 11th warmest of the 12 months.
Expect about 109 mm of rain on roughly 9 days, which makes January a wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 9 h 49 min on an average January day.
The nearest other city in this atlas is Fairfield (13 km away). In January its highs average 13.7°C, about as warm as Vacaville, with 109 mm of rain.
Among the 498 cities listed in the United States, Vacaville ranks joint 164th of 498 for the warmest January highs and joint 441st of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; Vacaville is 4.6°C warmer than that mean.
From January to February, average highs rise by 1.7°C to 15.8°C, and monthly rainfall falls from 109 mm to 108 mm.
The annual picture
January 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, selected | 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 | 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
January in nearby cities
- Fairfield in JanuaryUnited States · 13 kmHigh 13.7°C · Low 5.4°C · 109 mm rain
- Napa in JanuaryUnited States · 27 kmHigh 14.4°C · Low 5.3°C · 116 mm rain
- Vallejo in JanuaryUnited States · 37 kmHigh 14.0°C · Low 5.1°C · 101 mm rain
- Antioch in JanuaryUnited States · 42 kmHigh 13.9°C · Low 5.9°C · 93 mm rain
- Concord (California), United States in JanuaryUnited States · 42 kmHigh 13.9°C · Low 5.6°C · 93 mm rain
- Sacramento in JanuaryUnited States · 50 kmHigh 13.5°C · Low 4.3°C · 118 mm rain
- Elk Grove in JanuaryUnited States · 54 kmHigh 13.3°C · Low 4.3°C · 125 mm rain
- Berkeley in JanuaryUnited States · 59 kmHigh 13.7°C · Low 5.4°C · 93 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.