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

Planting zone for 95955 — Maxwell, CA

ZIP code 95955 (Maxwell, Colusa County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 14 and the first fall frost December 1.

Where ZIP 95955 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 14
First frostDec 1
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 Maxwell, 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 Maxwell, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 14median — 50% chance of a later frost
Safe for tender plantsMarch 31only 10% chance of frost after
First fall frostDecember 1median — 10% chance by Nov 11
Growing season293 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 8 and returns around December 15.

From the NOAA station Colusa 2 Ssw, CA — 12 miles away, elevation 49 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 95955

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 3 – Jan 17
SpinachSow outdoors · Jan 3 – Jan 24
Broccoli, cabbageStart indoors · Dec 6 – Dec 20
Broccoli, cabbageTransplant · Jan 24 – Feb 7
Onion setsPlant outdoors · Jan 17 – Jan 31
PotatoesPlant outdoors · Jan 24 – Feb 7
LettuceSow outdoors · Jan 17 – Jan 31
Carrots, beetsSow outdoors · Jan 24 – Feb 7
TomatoesStart indoors · Dec 20 – Jan 3
TomatoesTransplant · Feb 21 – Mar 7
Peppers, eggplantStart indoors · Dec 6 – Dec 20
Peppers, eggplantTransplant · Feb 28 – Mar 14
BeansSow outdoors · Feb 21 – Mar 7
Sweet cornSow outdoors · Feb 21 – Mar 7
Cucumbers, squashSow outdoors · Feb 21 – Mar 7
Fall lettuce, spinachSow outdoors · Oct 6 – Oct 20
GarlicPlant cloves · Nov 17 – Dec 22
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 14) and first fall frost (Dec 1) 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 95955 came on Jan 31 — 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 Maxwell, CA

The soil mapped at the center of ZIP 95955 is Capay — clay loam, moderately well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up
pH6.4slightly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Capay clay loam, 0 percent slopes, low precip, MLRA 17.

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 95955; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Maxwell, CA

Summer high92 °Faverage high, July
Winter low38 °Faverage low, January
Hot days85days a year at 90 °F or more
Freezing nights17nights a year at 32 °F or less
Growing degree days4,582base 50 °F — the season’s usable heat
Longest day14 h 56 mindaylight on June 21
Shortest day9 h 24 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation17.2 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 55 °F, low 38 °F 55°38° JanFebruary: average high 60 °F, low 41 °F 60°41° FebMarch: average high 67 °F, low 44 °F 67°44° MarApril: average high 73 °F, low 46 °F 73°46° AprMay: average high 81 °F, low 53 °F 81°53° MayJune: average high 88 °F, low 59 °F 88°59° JunJuly: average high 92 °F, low 60 °F 92°60° JulAugust: average high 92 °F, low 58 °F 92°58° AugSeptember: average high 89 °F, low 54 °F 89°54° SepOctober: average high 79 °F, low 48 °F 79°48° OctNovember: average high 64 °F, low 42 °F 64°42° NovDecember: average high 55 °F, low 38 °F 55°38° Dec

Precipitation by month inches

0″1″2″3″4″January: 3.58 in precipitation 3.6 JanFebruary: 2.97 in precipitation 3.0 FebMarch: 2.19 in precipitation 2.2 MarApril: 1.00 in precipitation 1.0 AprMay: 0.84 in precipitation 0.8 MayJune: 0.51 in precipitation 0.5 JunJuly: 0.01 in precipitation 0.0 JulAugust: 0.03 in precipitation 0.0 AugSeptember: 0.11 in precipitation 0.1 SepOctober: 0.87 in precipitation 0.9 OctNovember: 1.91 in precipitation 1.9 NovDecember: 3.17 in precipitation 3.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Colusa 2 Ssw, CA (12 mi away); precipitation: Colusa 2 Ssw, CA (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

959329b
Colusa, CA · 11 mi
959709b
Princeton, CA · 11 mi
959879b
Williams, CA · 13 mi
959799a
Stonyford, CA · 15 mi
959889b
Willows, CA · 15 mi
959209b
Butte City, CA · 18 mi
959439b
Glenn, CA · 21 mi
959129b
Arbuckle, CA · 21 mi

California planting zones →

Questions about 95955

What planting zone is ZIP code 95955?

ZIP code 95955 (Maxwell, 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 Maxwell, CA?

The median last spring frost (32 °F) near 95955 is February 14; after March 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Colusa 2 Ssw station.

When is the first frost in Maxwell, CA?

The median first fall frost near 95955 is December 1, giving a median frost-free growing season of 293 days.

When should I plant tomatoes in 95955?

Start tomato seeds indoors around Dec 20 – Jan 3 and set transplants outside around Feb 21 – Mar 7, one to three weeks after the median last frost.

How much rain and snow does 95955 get?

About 17.2 inches of precipitation a year (NOAA 1991–2020 normals, Colusa 2 Ssw station).

How hot do summers get in Maxwell, CA?

The average high peaks at 92 °F in July, with about 85 days a year at 90 °F or more.

What kind of soil does 95955 have?

The USDA soil survey maps Capay at the center of ZIP 95955: clay loam, moderately well drained, pH about 6.4 (slightly acidic).

Did spring come early in Maxwell, CA in 2026?

Spring leaf-out near 95955 came on Jan 31 in 2026, about the same as the 1991–2020 average (Jan 31), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Maxwell, CA?

Intermediate onions: the longest day near 95955 is 14 h 56 min, so day-neutral types bulb best; long-day varieties may not bulb fully.