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

Planting zone for 95631 — Foresthill, CA

ZIP code 95631 (Foresthill, Placer County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is April 12 and the first fall frost November 21.

Where ZIP 95631 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.

Zone9a20 to 25 °F
Coldest night−6.7 to −3.9 °C
Last frostApr 12
First frostNov 21
2012 zone9a

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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Foresthill, 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 Foresthill, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 12median — 50% chance of a later frost
Safe for tender plantsMay 10only 10% chance of frost after
First fall frostNovember 21median — 10% chance by Oct 29
Growing season221 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 13 and returns around December 8.

From the NOAA station Georgetown Rs, CA — 9 miles away, elevation 3,002 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 95631

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 1 – Mar 15
SpinachSow outdoors · Mar 1 – Mar 22
Broccoli, cabbageStart indoors · Feb 1 – Feb 15
Broccoli, cabbageTransplant · Mar 22 – Apr 5
Onion setsPlant outdoors · Mar 15 – Mar 29
PotatoesPlant outdoors · Mar 22 – Apr 5
LettuceSow outdoors · Mar 15 – Mar 29
Carrots, beetsSow outdoors · Mar 22 – Apr 5
TomatoesStart indoors · Feb 15 – Mar 1
TomatoesTransplant · Apr 19 – May 3
Peppers, eggplantStart indoors · Feb 1 – Feb 15
Peppers, eggplantTransplant · Apr 26 – May 10
BeansSow outdoors · Apr 19 – May 3
Sweet cornSow outdoors · Apr 19 – May 3
Cucumbers, squashSow outdoors · Apr 19 – May 3
Fall lettuce, spinachSow outdoors · Sep 26 – Oct 10
GarlicPlant cloves · Nov 7 – Dec 12
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 12) and first fall frost (Nov 21) 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 95631 came on Jan 24 — 18 days earlier than the 1991–2020 average (Feb 11).

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 Foresthill, CA

The soil mapped at the center of ZIP 95631 is Cohasset — cobbly slightly decomposed plant material, well drained.

TextureCobbly slightly decomposed plant materialtop layer
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter80%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Cohasset cobbly loam, 15 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 95631; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Foresthill, CA

Summer high91 °Faverage high, July
Winter low36 °Faverage low, January
Hot days58days a year at 90 °F or more
Freezing nights49nights a year at 32 °F or less
Growing degree days3,939base 50 °F — the season’s usable heat
Longest day14 h 55 mindaylight on June 21
Shortest day9 h 25 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation55.5 inper year, rain and melted snow
Snowfall3 inper year; 1 days with snow on the ground

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 52 °F, low 36 °F 52°36° JanFebruary: average high 55 °F, low 36 °F 55°36° FebMarch: average high 59 °F, low 38 °F 59°38° MarApril: average high 64 °F, low 41 °F 64°41° AprMay: average high 72 °F, low 48 °F 72°48° MayJune: average high 82 °F, low 56 °F 82°56° JunJuly: average high 91 °F, low 63 °F 91°63° JulAugust: average high 91 °F, low 63 °F 91°63° AugSeptember: average high 86 °F, low 57 °F 86°57° SepOctober: average high 74 °F, low 49 °F 74°49° OctNovember: average high 59 °F, low 41 °F 59°41° NovDecember: average high 50 °F, low 36 °F 50°36° Dec

Precipitation by month inches · ❄ = snowfall

0″2″4″6″8″10″January: 9.86 in precipitation, 0.1 in snowfall 9.9 JanFebruary: 9.07 in precipitation, 0.5 in snowfall 9.1❄1 FebMarch: 8.67 in precipitation, 1.8 in snowfall 8.7❄2 MarApril: 4.56 in precipitation 4.6 AprMay: 2.91 in precipitation 2.9 MayJune: 0.83 in precipitation 0.8 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.10 in precipitation 0.1 AugSeptember: 0.63 in precipitation 0.6 SepOctober: 2.85 in precipitation 2.9 OctNovember: 5.58 in precipitation, 0.1 in snowfall 5.6 NovDecember: 10.49 in precipitation, 0.1 in snowfall 10.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Georgetown Rs, CA (9 mi away); precipitation: Foresthill Rs, CA (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

957179a
Gold Run, CA · 8 mi
957139a
Colfax, CA · 10 mi
956349a
Georgetown, CA · 11 mi
957149a
Dutch Flat, CA · 11 mi
957018b
Alta, CA · 12 mi
957369a
Weimar, CA · 12 mi
957129a
Chicago Park, CA · 13 mi
956359b
Greenwood, CA · 13 mi

California planting zones →

Questions about 95631

What planting zone is ZIP code 95631?

ZIP code 95631 (Foresthill, CA) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in Foresthill, CA?

The median last spring frost (32 °F) near 95631 is April 12; after May 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Georgetown Rs station.

When is the first frost in Foresthill, CA?

The median first fall frost near 95631 is November 21, giving a median frost-free growing season of 221 days.

When should I plant tomatoes in 95631?

Start tomato seeds indoors around Feb 15 – Mar 1 and set transplants outside around Apr 19 – May 3, one to three weeks after the median last frost.

How much rain and snow does 95631 get?

About 55.5 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Foresthill Rs station).

How hot do summers get in Foresthill, CA?

The average high peaks at 91 °F in July, with about 58 days a year at 90 °F or more.

What kind of soil does 95631 have?

The USDA soil survey maps Cohasset at the center of ZIP 95631: cobbly slightly decomposed plant material, well drained, pH about 5.5 (moderately acidic).

Did spring come early in Foresthill, CA in 2026?

Spring leaf-out near 95631 came on Jan 24 in 2026, 18 days earlier than the 1991–2020 average (Feb 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Foresthill, CA?

Intermediate onions: the longest day near 95631 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.