Photo: Sanfranman59 · CC BY-SA 3.0Vallejo’s winters are milder and less snowy than most of the U.S.
A typical July afternoon reaches 75°, a January night drops to 43°, and snow is almost unheard of.
A year in Vallejo at a glance
Each month’s typical high and low, and what it brings.
What stands out about Vallejo’s climate
Compared with towns across the U.S., with Vallejo’s place in California beside it.
What a year in Vallejo feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
Frost is rare
Day counts come from NOAA’s station at Napa Co Airport, 7 miles from the city’s center point, at about the same height; frost dates and degree days from Berkeley, CA, 16 miles away.
The 2023 USDA map puts Vallejo’s center in zone 9b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 27°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 22 inches of rain a year
January is the wettest month and July the driest. Rain falls on about 67 days a year. Snow is rare: about 0.0" in a normal year at Berkeley, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Vallejo
93% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from December through February.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Berkeley, CA.
Living with Vallejo’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 9b. Frost comes about 1 winter in 4, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: March, April, May, June, July, August, September, October and November. 49 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Vallejo from natural hazards, earthquakes are the largest share (56%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Vallejo and its neighbors
Benicia has the coldest January nights next door (40°, 3° colder) and Benicia the hottest July afternoons (84°, 8° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Vallejo’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Vallejo, CA | 43° | 75° | 22" | 0.0" |
| Makawao, HI | 53° | 75° | 23" | 0.0" |
| Camano, WA | 35° | 73° | 30" | 2.5" |
| Cedar Mill, OR | 36° | 81° | 39" | 3.6" |
| Hayden, ID | 25° | 83° | 26" | 27" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Vallejo averaged 1.5° warmer than the 1900s. The biggest change is in January (+2.3°).
A bigger shift than in 62% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods. In a city of 123,000 people, part of the change is the city itself: pavement and buildings hold heat (the urban heat island).
How Vallejo compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Vallejo’s place among California’s.
Vallejo weather by month
Highs, lows and precipitation from NOAA’s grid at Vallejo’s center; snow, wet days and snow on the ground from Berkeley, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 57° | 43° | 4.4" | 0.0" | 11 | 0 | 46° – 55° |
| February | 61° | 45° | 4.1" | 0.0" | 11 | 0 | 48° – 57° |
| March | 64° | 47° | 3.3" | 0.0" | 10 | 0 | 50° – 61° |
| April | 67° | 48° | 1.5" | 0.0" | 7 | 0 | 53° – 61° |
| May | 70° | 52° | 0.7" | 0.0" | 3 | 0 | 56° – 66° |
| June | 75° | 55° | 0.2" | 0.0" | 1 | 0 | 62° – 67° |
| July | 75° | 56° | 0.0" | 0.0" | 0 | 0 | 63° – 69° |
| August | 76° | 56° | 0.0" | 0.0" | 1 | 0 | 63° – 71° |
| September | 76° | 56° | 0.1" | 0.0" | 1 | 0 | 62° – 70° |
| October | 72° | 53° | 1.0" | 0.0" | 3 | 0 | 60° – 68° |
| November | 64° | 47° | 2.3" | 0.0" | 7 | 0 | 49° – 60° |
| December | 57° | 42° | 4.0" | 0.0" | 11 | 0 | 46° – 55° |
| Year | 68° | 50° | 21.5" | 0.0" | 67 | 0 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 49° to 60°. June is the most reliable, staying within 6°.
Where Vallejo’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Vallejo’s center.
- Snow: Berkeley, CA.
- Frost dates, heating and cooling: Berkeley, CA, 16 miles away.
- Freezing nights, 90° and 100° days: Napa Co Airport, 7 miles from the city’s center point, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Vallejo’s climate
What is the weather like in Vallejo?
A typical July afternoon reaches 75°, a January night drops to 43°, and snow is almost unheard of. Milder January nights than 91% of U.S. towns; cooler July afternoons than 98% of U.S. towns.
How cold does it get in Vallejo in winter?
December nights average 42°. About 34 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 46°.
How much snow does Vallejo get?
About 0.0 inches in a normal winter at Berkeley, CA, so most winters see none.
How hot does it get in Vallejo?
July, with a typical high of 75° and a low of 56°. About 16 days a year reach 90° and 2 reach 100° (Berkeley, CA).
When is the first and last frost in Vallejo?
Most years have no frost at all: a 32° night comes in about 27% of winters at Berkeley, CA, usually in December or January.
What growing zone is Vallejo in?
Zone 9b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 27°.
What is the best time of year to visit Vallejo?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May, June, July, August, September, October and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Vallejo getting warmer?
Yes: 1991–2020 averaged 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 62% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Vallejo.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.