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

Planting zone for 95552 — Mad River, CA

ZIP code 95552 (Mad River, Trinity County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is March 4 and the first fall frost November 22.

Where ZIP 95552 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.

Zone8b15 to 20 °F
Coldest night−9.4 to −6.7 °C
Last frostMar 4
First frostNov 22
2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mad River, 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 Mad River, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 4median — 50% chance of a later frost
Safe for tender plantsApril 8only 10% chance of frost after
First fall frostNovember 22median — 10% chance by Nov 1
Growing season264 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 19 and returns around December 8.

From the NOAA station Grizzly Creek Sp, CA — 28 miles away, elevation 413 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 95552

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 21 – Feb 4
SpinachSow outdoors · Jan 21 – Feb 11
Broccoli, cabbageStart indoors · Dec 24 – Jan 7
Broccoli, cabbageTransplant · Feb 11 – Feb 25
Onion setsPlant outdoors · Feb 4 – Feb 18
PotatoesPlant outdoors · Feb 11 – Feb 25
LettuceSow outdoors · Feb 4 – Feb 18
Carrots, beetsSow outdoors · Feb 11 – Feb 25
TomatoesStart indoors · Jan 7 – Jan 21
TomatoesTransplant · Mar 11 – Mar 25
Peppers, eggplantStart indoors · Dec 24 – Jan 7
Peppers, eggplantTransplant · Mar 18 – Apr 1
BeansSow outdoors · Mar 11 – Mar 25
Sweet cornSow outdoors · Mar 11 – Mar 25
Cucumbers, squashSow outdoors · Mar 11 – Mar 25
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 (Mar 4) 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 95552 came on Feb 7 — 22 days earlier than the 1991–2020 average (Mar 1).

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 Mad River, CA

The soil mapped at the center of ZIP 95552 is Oxalis family — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Oxalis-Hecker-Doty families association, deep, 25 to 70 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 95552; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mad River, CA

Summer high73 °Faverage high, July
Winter low38 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights23nights a year at 32 °F or less
Growing degree days1,908base 50 °F — the season’s usable heat
Longest day15 h 03 mindaylight on June 21
Shortest day9 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation70.3 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°32 °FJanuary: average high 50 °F, low 38 °F 50°38° JanFebruary: average high 52 °F, low 39 °F 52°39° FebMarch: average high 55 °F, low 41 °F 55°41° MarApril: average high 60 °F, low 43 °F 60°43° AprMay: average high 65 °F, low 48 °F 65°48° MayJune: average high 69 °F, low 50 °F 69°50° JunJuly: average high 73 °F, low 53 °F 73°53° JulAugust: average high 73 °F, low 53 °F 73°53° AugSeptember: average high 72 °F, low 49 °F 72°49° SepOctober: average high 63 °F, low 45 °F 63°45° OctNovember: average high 54 °F, low 40 °F 54°40° NovDecember: average high 49 °F, low 38 °F 49°38° Dec

Precipitation by month inches

0″2″4″6″8″10″12″14″January: 12.36 in precipitation 12.4 JanFebruary: 10.46 in precipitation 10.5 FebMarch: 9.43 in precipitation 9.4 MarApril: 6.03 in precipitation 6.0 AprMay: 3.75 in precipitation 3.8 MayJune: 1.33 in precipitation 1.3 JunJuly: 0.25 in precipitation 0.3 JulAugust: 0.21 in precipitation 0.2 AugSeptember: 1.03 in precipitation 1.0 SepOctober: 3.61 in precipitation 3.6 OctNovember: 8.63 in precipitation 8.6 NovDecember: 13.17 in precipitation 13.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Grizzly Creek Sp, CA (28 mi away); precipitation: Bridgeville 5.2 Ene, CA (17 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

955149a
Blocksburg, CA · 14 mi
955119a
Alderpoint, CA · 15 mi
955269a
Bridgeville, CA · 16 mi
960418b
Hayfork, CA · 16 mi
960468b
Hyampom, CA · 18 mi
955549b
Myers Flat, CA · 19 mi
955599a
Phillipsville, CA · 20 mi
955958b
Zenia, CA · 23 mi

California planting zones →

Questions about 95552

What planting zone is ZIP code 95552?

ZIP code 95552 (Mad River, CA) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Mad River, CA?

The median last spring frost (32 °F) near 95552 is March 4; after April 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Grizzly Creek Sp station.

When is the first frost in Mad River, CA?

The median first fall frost near 95552 is November 22, giving a median frost-free growing season of 264 days.

When should I plant tomatoes in 95552?

Start tomato seeds indoors around Jan 7 – Jan 21 and set transplants outside around Mar 11 – Mar 25, one to three weeks after the median last frost.

How much rain and snow does 95552 get?

About 70.3 inches of precipitation a year (NOAA 1991–2020 normals, Bridgeville 5.2 Ene station).

How hot do summers get in Mad River, CA?

The average high peaks at 73 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 95552 have?

The USDA soil survey maps Oxalis family at the center of ZIP 95552: silty clay loam, poorly drained, pH about 6.2 (slightly acidic).

Did spring come early in Mad River, CA in 2026?

Spring leaf-out near 95552 came on Feb 7 in 2026, 22 days earlier than the 1991–2020 average (Mar 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mad River, CA?

Long-day onions: the longest day near 95552 is 15 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).