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

Planting zone for 94553 — Martinez, CA

ZIP code 94553 (Martinez, Contra Costa County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 28 and the first fall frost November 22.

Where ZIP 94553 is

Outlined: the ZIP code area · 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
Coldest night−3.9 to −1.1 °C
Last frostFeb 28
First frostNov 22
2012 zone9b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Martinez, 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 Martinez, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 28median — 50% chance of a later frost
Safe for tender plantsApril 5only 10% chance of frost after
First fall frostNovember 22median — 10% chance by Nov 7
Growing season266 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 23 and returns around December 9.

From the NOAA station Martinez Wtp, CA — 3 miles away, elevation 39 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 94553

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 17 – Jan 31
SpinachSow outdoors · Jan 17 – Feb 7
Broccoli, cabbageStart indoors · Dec 20 – Jan 3
Broccoli, cabbageTransplant · Feb 7 – Feb 21
Onion setsPlant outdoors · Jan 31 – Feb 14
PotatoesPlant outdoors · Feb 7 – Feb 21
LettuceSow outdoors · Jan 31 – Feb 14
Carrots, beetsSow outdoors · Feb 7 – Feb 21
TomatoesStart indoors · Jan 3 – Jan 17
TomatoesTransplant · Mar 7 – Mar 21
Peppers, eggplantStart indoors · Dec 20 – Jan 3
Peppers, eggplantTransplant · Mar 14 – Mar 28
BeansSow outdoors · Mar 7 – Mar 21
Sweet cornSow outdoors · Mar 7 – Mar 21
Cucumbers, squashSow outdoors · Mar 7 – Mar 21
Fall lettuce, spinachSow outdoors · Sep 27 – Oct 11
GarlicPlant cloves · Nov 8 – Dec 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 28) and first fall frost (Nov 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 94553 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 Martinez, CA

The soil mapped at the center of ZIP 94553 is Los Gatos — loam, well drained.

TextureLoama good balance for most vegetables
pH6.1slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Los Gatos loam, 50 to 75 percent slopes.

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 94553; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Martinez, CA

Summer high88 °Faverage high, July
Winter low35 °Faverage low, January
Hot days47days a year at 90 °F or more
Freezing nights16nights a year at 32 °F or less
Growing degree days3,421base 50 °F — the season’s usable heat
Longest day14 h 48 mindaylight on June 21
Shortest day9 h 31 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation23.1 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 56 °F, low 35 °F 56°35° JanFebruary: average high 61 °F, low 37 °F 61°37° FebMarch: average high 66 °F, low 40 °F 66°40° MarApril: average high 71 °F, low 43 °F 71°43° AprMay: average high 78 °F, low 46 °F 78°46° MayJune: average high 85 °F, low 50 °F 85°50° JunJuly: average high 88 °F, low 51 °F 88°51° JulAugust: average high 87 °F, low 51 °F 87°51° AugSeptember: average high 84 °F, low 50 °F 84°50° SepOctober: average high 76 °F, low 46 °F 76°46° OctNovember: average high 64 °F, low 39 °F 64°39° NovDecember: average high 57 °F, low 35 °F 57°35° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 4.37 in precipitation 4.4 JanFebruary: 4.60 in precipitation 4.6 FebMarch: 3.49 in precipitation 3.5 MarApril: 1.80 in precipitation 1.8 AprMay: 0.74 in precipitation 0.7 MayJune: 0.22 in precipitation 0.2 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.04 in precipitation 0.0 AugSeptember: 0.09 in precipitation 0.1 SepOctober: 0.98 in precipitation 1.0 OctNovember: 2.39 in precipitation 2.4 NovDecember: 4.33 in precipitation 4.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Martinez Wtp, CA (3 mi away); precipitation: Martinez 2.2 Sw, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

945239b
Pleasant Hill, CA · 5 mi
945699b
Port Costa, CA · 5 mi
945729b
Rodeo, CA · 5 mi
945499b
Lafayette, CA · 6 mi
945479b
Hercules, CA · 6 mi
945259b
Crockett, CA · 6 mi
945979b
Walnut Creek, CA · 6 mi
945649b
Pinole, CA · 6 mi

California planting zones →

Questions about 94553

What planting zone is ZIP code 94553?

ZIP code 94553 (Martinez, CA) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

When is the last frost in Martinez, CA?

The median last spring frost (32 °F) near 94553 is February 28; after April 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Martinez Wtp station.

When is the first frost in Martinez, CA?

The median first fall frost near 94553 is November 22, giving a median frost-free growing season of 266 days.

When should I plant tomatoes in 94553?

Start tomato seeds indoors around Jan 3 – Jan 17 and set transplants outside around Mar 7 – Mar 21, one to three weeks after the median last frost.

How much rain and snow does 94553 get?

About 23.1 inches of precipitation a year (NOAA 1991–2020 normals, Martinez 2.2 Sw station).

How hot do summers get in Martinez, CA?

The average high peaks at 88 °F in July, with about 47 days a year at 90 °F or more.

What kind of soil does 94553 have?

The USDA soil survey maps Los Gatos at the center of ZIP 94553: loam, well drained, pH about 6.1 (slightly acidic).

Did spring come early in Martinez, CA in 2026?

Spring leaf-out near 94553 came on Jan 29 in 2026, about the same as the 1991–2020 average (Jan 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Martinez, CA?

Intermediate onions: the longest day near 94553 is 14 h 48 min, so day-neutral types bulb best; long-day varieties may not bulb fully.