Vallejo, California climate: Normal weather by month, frost dates and records
Vallejo's normal year runs from 42°F January nights to 86°F September afternoons, with 21.5 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 16.4°C, January lows of 6°C, September highs of 30°C, 546 mm of precipitation a year.
- NOAA stationVallejo
- Station IDUSC00049219
- Location38.10°N 122.19°W
- Elevation341 ft (104 m)
- From the center4 miles
- Population123,475
On October 24, the normal high in Vallejo is 76°F and the normal low 52°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Vallejo.
- Jan 57° 42°
- Feb 63° 45°
- Mar 68° 46°
- Apr 73° 47°
- May 78° 51°
- Jun 83° 54°
- Jul 85° 56°
- Aug 86° 56°
- Sep 86° 57°
- Oct 79° 54°
- Nov 66° 47°
- Dec 58° 42°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Vallejo each month?
September is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 42°F. The most precipitation falls in December (4.49 in), the least in July (0.00 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 57°F | 42°F | 49.7°F | 4.46 | – | <1 | 2 | 9 h 50 min |
| February | 63°F | 45°F | 54.1°F | 3.58 | – | <1 | 1 | 10 h 50 min |
| March | 68°F | 46°F | 57.2°F | 3.18 | – | <1 | <1 | 11 h 50 min |
| April | 73°F | 47°F | 60.0°F | 1.45 | – | 1 | <1 | 13 h 10 min |
| May | 78°F | 51°F | 64.7°F | 0.80 | – | 2 | <1 | 14 h 10 min |
| June | 83°F | 54°F | 68.6°F | 0.22 | – | 6 | <1 | 14 h 50 min |
| July | 85°F | 56°F | 70.6°F | 0.00 | – | 7 | <1 | 14 h 30 min |
| August | 86°F | 56°F | 71.1°F | 0.04 | – | 8 | <1 | 13 h 40 min |
| September | 86°F | 57°F | 71.3°F | 0.08 | – | 10 | <1 | 12 h 30 min |
| October | 79°F | 54°F | 66.3°F | 1.02 | – | 3 | <1 | 11 h 20 min |
| November | 66°F | 47°F | 56.3°F | 2.17 | – | <1 | 1 | 10 h 10 min |
| December | 58°F | 42°F | 49.8°F | 4.49 | – | <1 | 1 | 9 h 30 min |
| Year (annual) | 74°F | 50°F | 61.6°F | 21.49 | – | 36 | 5 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 6°C | 9.8°C | 113 mm |
| February | 17°C | 7°C | 12.3°C | 91 mm |
| March | 20°C | 8°C | 14.0°C | 81 mm |
| April | 23°C | 8°C | 15.6°C | 37 mm |
| May | 26°C | 11°C | 18.2°C | 20 mm |
| June | 28°C | 12°C | 20.3°C | 6 mm |
| July | 30°C | 13°C | 21.4°C | 0 mm |
| August | 30°C | 13°C | 21.7°C | 1 mm |
| September | 30°C | 14°C | 21.8°C | 2 mm |
| October | 26°C | 12°C | 19.1°C | 26 mm |
| November | 19°C | 8°C | 13.5°C | 55 mm |
| December | 14°C | 6°C | 9.9°C | 114 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00049219; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Vallejo?
Normal highs sit between 65°F and 85°F in March, April, May, June, October and November.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00049219.
When is the last frost in Vallejo?
In Vallejo, the last spring frost (32°F) comes after January 17 in half of years and after March 4 in one year in ten; the first autumn frost comes before December 27 in half of years and before December 4 in one year in ten. A night at 32°F or colder comes at all in 75% of years here (NOAA).
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- January 171 year in 10 after March 4; 9 in 10 after December 23
- First autumn frost, half of years before
- December 271 year in 10 before December 4; 9 in 10 before February 4
NOAA puts the median frost-free season at 346 days, and the season without a hard freeze (28°F) at 365 days.
A hard freeze (28°F) comes after January 5 in half of springs and before January 2 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Vallejo in zone 9b across its 4 ZIP code areas (9b in 94591, the largest).
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00049219; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Vallejo ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Vallejo's 4 ZIP code areas are all in zone 9b. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Vallejo?
In a normal year in Vallejo, 36 days a year reach 90°F (7 of them 100°F or more) and 5 nights fall to 32°F or colder.
- Days at 90°F or more
- 36a normal year
- Days at 100°F or more
- 7a normal year
- Nights at 32°F or colder
- 5a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00049219.
How sunny is Vallejo?
Over a year 87% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Vallejo, 5.1 kWh per square metre a day. July is the sunniest month (95%) and December the cloudiest (72%). Among the 459 U.S. places of 50,000 or more, that ranks tied 58th (with 22 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 74% | 2.3 |
| February | 77% | 3.3 |
| March | 78% | 4.6 |
| April | 84% | 6.1 |
| May | 88% | 7.3 |
| June | 93% | 8.1 |
| July | 95% | 8.0 |
| August | 94% | 7.1 |
| September | 93% | 5.8 |
| October | 88% | 4.2 |
| November | 81% | 2.8 |
| December | 72% | 2.0 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Vallejo need?
A normal year in Vallejo brings 2,093 heating degree days, 61% fewer than the median U.S. place (5,373), and 868 cooling degree days, 4% fewer than the median (908). Three months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,389 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 476 | 0 |
| February | 309 | 2 |
| March | 248 | 5 |
| April | 168 | 16 |
| May | 66 | 55 |
| June | 18 | 126 |
| July | 4 | 176 |
| August | 2 | 190 |
| September | 7 | 196 |
| October | 54 | 94 |
| November | 270 | 8 |
| December | 471 | 0 |
| Year (annual) | 2,093 | 868 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00049219. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Vallejo been warmer than normal lately?
2025 averaged 61.4°F, 0.3°F below the 1991-2020 normal of 61.6°F. 2 of the 3 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 61.9°F | +0.3°F | 12.59 |
| 2024 | 62.8°F | +1.1°F | 20.74 |
| 2025 | 61.4°F | −0.3°F | 15.86 |
Source: observed years: ACIS, station USC00049219. A year counts only with all twelve months complete.
How does Vallejo's climate compare?
Vallejo is warmer than 113 of the other 218 places with their own NOAA record in California, and wetter than 143. Across the 7,247 U.S. stations with normals, its annual mean of 61.6°F is warmer than 79%.
In the Köppen classification computed from these normals, Vallejo is Csb: temperate, dry-summer, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Vallejo share this climate record?
5 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Hercules, CA26,499 people · 8 mi SW
- Benicia, CA26,477 people · 3 mi SE
- Rodeo, CA8,735 people · 6 mi SW
- Crockett, CA3,642 people · 4 mi SW
- Port Costa, CA194 people · 4 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Vallejo's climate
What is the coldest month in Vallejo?
January, with a normal high of 57°F and a normal low of 42°F. The warmest is September (86°F by day, 57°F at night).
What is the rainiest month in Vallejo?
December, with 4.49 in of precipitation in a normal year; the driest is July with 0.00 in.
What plant hardiness zone is Vallejo in?
The USDA's 2023 map puts Vallejo in zone 9b across its 4 ZIP code areas (9b in 94591, the largest).
How late can frost come in Vallejo?
In half of years the last 32°F night comes after January 17; in one year in ten it comes after March 4. Waiting until March 4 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Vallejo in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- Martinez, CA7 miles from this station, 58.2°F a year
- Napa, CA9 miles from this station, 57.7°F a year
- Concord Wastewater Treatment Plant, CA11 miles from this station, 62.4°F a year
- Concord, CA11 miles from this station, 62.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made