Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for Vacaville, CA

Vacaville, CA is in USDA zone 9b across its 3 ZIP codes. The median last spring frost is January 31 and the first fall frost December 11.

Vacaville on the zone map

Outlined: its 2 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone9b25 to 30 °F
ZIP codes3
Last frostJan 31
First frostDec 11
Growing season318 days

9b 3 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Vacaville, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 31median — 50% chance of a later frost
Safe for tender plantsMarch 11only 10% chance of frost after
First fall frostDecember 11median — 10% chance by Nov 24
Growing season318 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 6 and returns around December 23.

From the NOAA station Vacaville, CA, elevation 112 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in Vacaville

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 20 – Jan 3
SpinachSow outdoors · Dec 20 – Jan 10
Broccoli, cabbageStart indoors · Nov 22 – Dec 6
Broccoli, cabbageTransplant · Jan 10 – Jan 24
Onion setsPlant outdoors · Jan 3 – Jan 17
PotatoesPlant outdoors · Jan 10 – Jan 24
LettuceSow outdoors · Jan 3 – Jan 17
Carrots, beetsSow outdoors · Jan 10 – Jan 24
TomatoesStart indoors · Dec 6 – Dec 20
TomatoesTransplant · Feb 7 – Feb 21
Peppers, eggplantStart indoors · Nov 22 – Dec 6
Peppers, eggplantTransplant · Feb 14 – Feb 28
BeansSow outdoors · Feb 7 – Feb 21
Sweet cornSow outdoors · Feb 7 – Feb 21
Cucumbers, squashSow outdoors · Feb 7 – Feb 21
Fall lettuce, spinachSow outdoors · Oct 16 – Oct 30
GarlicPlant cloves · Nov 27 – Jan 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 31) and first fall frost (Dec 11) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 95696 came on Jan 29 — about the same time as the 1991–2020 average (Jan 31).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Vacaville, CA

The soil mapped at the center of ZIP 95696 is Dibble — loam, well drained.

TextureLoama good balance for most vegetables
pH6.1slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Dibble-Los Osos loams, 30 to 50 percent slopes, eroded.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 95696; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Vacaville, CA

Summer high97 °Faverage high, July
Winter low40 °Faverage low, January
Hot days102days a year at 90 °F or more
Freezing nights14nights a year at 32 °F or less
Growing degree days5,214base 50 °F — the season’s usable heat
Longest day14 h 51 mindaylight on June 21
Shortest day9 h 29 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation25.6 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 58 °F, low 40 °F 58°40° JanFebruary: average high 63 °F, low 42 °F 63°42° FebMarch: average high 69 °F, low 45 °F 69°45° MarApril: average high 75 °F, low 48 °F 75°48° AprMay: average high 83 °F, low 53 °F 83°53° MayJune: average high 91 °F, low 58 °F 91°58° JunJuly: average high 97 °F, low 60 °F 97°60° JulAugust: average high 97 °F, low 60 °F 97°60° AugSeptember: average high 92 °F, low 58 °F 92°58° SepOctober: average high 81 °F, low 52 °F 81°52° OctNovember: average high 67 °F, low 45 °F 67°45° NovDecember: average high 58 °F, low 40 °F 58°40° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 5.55 in precipitation 5.5 JanFebruary: 5.14 in precipitation 5.1 FebMarch: 3.37 in precipitation 3.4 MarApril: 1.23 in precipitation 1.2 AprMay: 0.78 in precipitation 0.8 MayJune: 0.22 in precipitation 0.2 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.06 in precipitation 0.1 AugSeptember: 0.13 in precipitation 0.1 SepOctober: 1.01 in precipitation 1.0 OctNovember: 2.44 in precipitation 2.4 NovDecember: 5.67 in precipitation 5.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Vacaville, CA (4 mi away); precipitation: Vacaville, CA (4 mi away). Daylight is calculated from latitude.

ZIP codes in Vacaville

956879b
25 to 30 °F
956889b
25 to 30 °F
956969b
25 to 30 °F

California planting zones →

Questions about Vacaville

What planting zone is Vacaville, CA?

Vacaville, CA is in USDA hardiness zone 9b on the 2023 map (9b: 25 to 30 °F).

When is the last frost in Vacaville, CA?

The median last spring frost is January 31 and the median first fall frost is December 11 (NOAA 1991–2020 normals, Vacaville station).

When can I plant a garden in Vacaville, CA?

Cool-season crops like peas and spinach go in around Dec 20 – Jan 10; tomatoes, peppers, beans and squash after about Feb 7, once frost risk has passed.

What kind of onions grow in Vacaville, CA?

Intermediate onions: the longest day is 14 h 51 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Vacaville, CA get?

About 25.6 inches of precipitation a year (NOAA 1991–2020 normals).