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

Planting zone for Danville, CA

Danville, CA is in USDA zone 9b across its 2 ZIP codes. The median last spring frost is March 8 and the first fall frost December 22.

Danville 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 codes2
Last frostMar 8
First frostDec 22
Growing season282 days

9b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Danville, CA…

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 Danville, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 8median — 50% chance of a later frost
Safe for tender plantsApril 15only 10% chance of frost after
First fall frostDecember 22median — 10% chance by Nov 23
Growing season282 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 8 and returns around January 16.

From the NOAA station Mt Diablo Junction, CA, elevation 2,169 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 Danville

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 25 – Feb 8
SpinachSow outdoors · Jan 25 – Feb 15
Broccoli, cabbageStart indoors · Dec 28 – Jan 11
Broccoli, cabbageTransplant · Feb 15 – Mar 1
Onion setsPlant outdoors · Feb 8 – Feb 22
PotatoesPlant outdoors · Feb 15 – Mar 1
LettuceSow outdoors · Feb 8 – Feb 22
Carrots, beetsSow outdoors · Feb 15 – Mar 1
TomatoesStart indoors · Jan 11 – Jan 25
TomatoesTransplant · Mar 15 – Mar 29
Peppers, eggplantStart indoors · Dec 28 – Jan 11
Peppers, eggplantTransplant · Mar 22 – Apr 5
BeansSow outdoors · Mar 15 – Mar 29
Sweet cornSow outdoors · Mar 15 – Mar 29
Cucumbers, squashSow outdoors · Mar 15 – Mar 29
Fall lettuce, spinachSow outdoors · Oct 27 – Nov 10
GarlicPlant cloves · Dec 8 – Jan 12
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 8) and first fall frost (Dec 22) 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 94526 came on Jan 29 — about the same time as the 1991–2020 average (Jan 30).

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 Danville, CA

The soil mapped at the center of ZIP 94526 is Diablo — clay, well drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Diablo clay, 5 to 25 percent slopes, MLRA 15.

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 94526; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Danville, CA

Summer high83 °Faverage high, July
Winter low41 °Faverage low, December
Hot days27days a year at 90 °F or more
Freezing nights19nights a year at 32 °F or less
Growing degree days3,645base 50 °F — the season’s usable heat
Longest day14 h 47 mindaylight on June 21
Shortest day9 h 32 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation21.5 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°32 °FJanuary: average high 54 °F, low 42 °F 54°42° JanFebruary: average high 55 °F, low 42 °F 55°42° FebMarch: average high 58 °F, low 43 °F 58°43° MarApril: average high 62 °F, low 44 °F 62°44° AprMay: average high 68 °F, low 49 °F 68°49° MayJune: average high 76 °F, low 55 °F 76°55° JunJuly: average high 83 °F, low 62 °F 83°62° JulAugust: average high 83 °F, low 61 °F 83°61° AugSeptember: average high 80 °F, low 60 °F 80°60° SepOctober: average high 72 °F, low 54 °F 72°54° OctNovember: average high 60 °F, low 46 °F 60°46° NovDecember: average high 53 °F, low 41 °F 53°41° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 4.17 in precipitation 4.2 JanFebruary: 4.41 in precipitation 4.4 FebMarch: 3.27 in precipitation 3.3 MarApril: 1.54 in precipitation 1.5 AprMay: 0.64 in precipitation 0.6 MayJune: 0.22 in precipitation 0.2 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.05 in precipitation 0.1 AugSeptember: 0.10 in precipitation 0.1 SepOctober: 0.86 in precipitation 0.9 OctNovember: 2.18 in precipitation 2.2 NovDecember: 4.02 in precipitation 4.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mt Diablo Junction, CA (6 mi away); precipitation: Walnut Creek 1.7 Sse, CA (5 mi away). Daylight is calculated from latitude.

ZIP codes in Danville

945069b
25 to 30 °F
945269b
25 to 30 °F

California planting zones →

Questions about Danville

What planting zone is Danville, CA?

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

When is the last frost in Danville, CA?

The median last spring frost is March 8 and the median first fall frost is December 22 (NOAA 1991–2020 normals, Mt Diablo Junction station).

When can I plant a garden in Danville, CA?

Cool-season crops like peas and spinach go in around Jan 25 – Feb 15; tomatoes, peppers, beans and squash after about Mar 15, once frost risk has passed.

What kind of onions grow in Danville, CA?

Intermediate onions: the longest day is 14 h 47 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Danville, CA get?

About 21.5 inches of precipitation a year (NOAA 1991–2020 normals).