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

Planting zone for 95562 — Rio Dell, CA

ZIP code 95562 (Rio Dell, Humboldt County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 1 and the first fall frost December 19.

Where ZIP 95562 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 1
First frostDec 19
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 Rio Dell, 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 Rio Dell, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 1median — 50% chance of a later frost
Safe for tender plantsMarch 8only 10% chance of frost after
First fall frostDecember 19median — 10% chance by Nov 19
Growing season328 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 3 and returns around December 31.

From the NOAA station Scotia, CA — 3 miles away, elevation 138 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 95562

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 21 – Jan 4
SpinachSow outdoors · Dec 21 – Jan 11
Broccoli, cabbageStart indoors · Nov 23 – Dec 7
Broccoli, cabbageTransplant · Jan 11 – Jan 25
Onion setsPlant outdoors · Jan 4 – Jan 18
PotatoesPlant outdoors · Jan 11 – Jan 25
LettuceSow outdoors · Jan 4 – Jan 18
Carrots, beetsSow outdoors · Jan 11 – Jan 25
TomatoesStart indoors · Dec 7 – Dec 21
TomatoesTransplant · Feb 8 – Feb 22
Peppers, eggplantStart indoors · Nov 23 – Dec 7
Peppers, eggplantTransplant · Feb 15 – Mar 1
BeansSow outdoors · Feb 8 – Feb 22
Sweet cornSow outdoors · Feb 8 – Feb 22
Cucumbers, squashSow outdoors · Feb 8 – Feb 22
Fall lettuce, spinachSow outdoors · Oct 24 – Nov 7
GarlicPlant cloves · Dec 5 – Jan 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 1) and first fall frost (Dec 19) 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 95562 came on Jan 29 — 3 days earlier than the 1991–2020 average (Feb 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 Rio Dell, CA

The soil mapped at the center of ZIP 95562 is Redwoodhouse — loam, well drained.

TextureLoama good balance for most vegetables
pH6.8neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter8%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Redwoodhouse-Yagercreek-Mailridge complex, 30 to 50 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 95562; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rio Dell, CA

Summer high73 °Faverage high, September
Winter low42 °Faverage low, December
Hot days2days a year at 90 °F or more
Freezing nights6nights a year at 32 °F or less
Growing degree days2,346base 50 °F — the season’s usable heat
Longest day15 h 04 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)
Precipitation47.7 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°32 °FJanuary: average high 57 °F, low 43 °F 57°43° JanFebruary: average high 58 °F, low 43 °F 58°43° FebMarch: average high 59 °F, low 44 °F 59°44° MarApril: average high 62 °F, low 45 °F 62°45° AprMay: average high 64 °F, low 49 °F 64°49° MayJune: average high 67 °F, low 51 °F 67°51° JunJuly: average high 70 °F, low 54 °F 70°54° JulAugust: average high 72 °F, low 54 °F 72°54° AugSeptember: average high 73 °F, low 52 °F 73°52° SepOctober: average high 69 °F, low 48 °F 69°48° OctNovember: average high 61 °F, low 45 °F 61°45° NovDecember: average high 55 °F, low 42 °F 55°42° Dec

Precipitation by month inches

0″2″4″6″8″10″January: 8.59 in precipitation 8.6 JanFebruary: 7.83 in precipitation 7.8 FebMarch: 6.93 in precipitation 6.9 MarApril: 3.89 in precipitation 3.9 AprMay: 1.91 in precipitation 1.9 MayJune: 0.57 in precipitation 0.6 JunJuly: 0.14 in precipitation 0.1 JulAugust: 0.05 in precipitation 0.1 AugSeptember: 0.47 in precipitation 0.5 SepOctober: 2.38 in precipitation 2.4 OctNovember: 5.23 in precipitation 5.2 NovDecember: 9.68 in precipitation 9.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Scotia, CA (3 mi away); precipitation: Scotia, CA (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

955659b
Scotia, CA · 5 mi
955369b
Ferndale, CA · 7 mi
955409b
Fortuna, CA · 9 mi
955479b
Hydesville, CA · 9 mi
955289b
Carlotta, CA · 10 mi
955719b
Weott, CA · 10 mi
955589b
Petrolia, CA · 11 mi
955459b
Honeydew, CA · 12 mi

California planting zones →

Questions about 95562

What planting zone is ZIP code 95562?

ZIP code 95562 (Rio Dell, 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 Rio Dell, CA?

The median last spring frost (32 °F) near 95562 is February 1; after March 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Scotia station.

When is the first frost in Rio Dell, CA?

The median first fall frost near 95562 is December 19, giving a median frost-free growing season of 328 days.

When should I plant tomatoes in 95562?

Start tomato seeds indoors around Dec 7 – Dec 21 and set transplants outside around Feb 8 – Feb 22, one to three weeks after the median last frost.

How much rain and snow does 95562 get?

About 47.7 inches of precipitation a year (NOAA 1991–2020 normals, Scotia station).

How hot do summers get in Rio Dell, CA?

The average high peaks at 73 °F in September, with about 2 days a year at 90 °F or more.

What kind of soil does 95562 have?

The USDA soil survey maps Redwoodhouse at the center of ZIP 95562: loam, well drained, pH about 6.8 (neutral).

Did spring come early in Rio Dell, CA in 2026?

Spring leaf-out near 95562 came on Jan 29 in 2026, 3 days earlier than the 1991–2020 average (Feb 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rio Dell, CA?

Long-day onions: the longest day near 95562 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).