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

Planting zone for 95646 — Kirkwood, CA

ZIP code 95646 (Kirkwood, Alpine County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is June 7 and the first fall frost September 28.

Where ZIP 95646 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostJun 7
First frostSep 28
2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Kirkwood, 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 Kirkwood, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 7median — 50% chance of a later frost
Safe for tender plantsJune 24only 10% chance of frost after
First fall frostSeptember 28median — 10% chance by Sep 10
Growing season113 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 25 and returns around October 12.

From the NOAA station Dagget Pass, NV — 25 miles away, elevation 7,333 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 95646

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 26 – May 10
SpinachSow outdoors · Apr 26 – May 17
Broccoli, cabbageStart indoors · Mar 29 – Apr 12
Broccoli, cabbageTransplant · May 17 – May 31
Onion setsPlant outdoors · May 10 – May 24
PotatoesPlant outdoors · May 17 – May 31
LettuceSow outdoors · May 10 – May 24
Carrots, beetsSow outdoors · May 17 – May 31
TomatoesStart indoors · Apr 12 – Apr 26
TomatoesTransplant · Jun 14 – Jun 28
Peppers, eggplantStart indoors · Mar 29 – Apr 12
Peppers, eggplantTransplant · Jun 21 – Jul 5
BeansSow outdoors · Jun 14 – Jun 28
Sweet cornSow outdoors · Jun 14 – Jun 28
Cucumbers, squashSow outdoors · Jun 14 – Jun 28
Fall lettuce, spinachSow outdoors · Aug 3 – Aug 17
GarlicPlant cloves · Sep 14 – Oct 19
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 7) and first fall frost (Sep 28) 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 95646 came on Mar 22 — 50 days earlier than the 1991–2020 average (May 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 Kirkwood, CA

The soil mapped at the center of ZIP 95646 is Lithnip — extremely gravelly sandy loam, somewhat excessively drained.

TextureExtremely gravelly sandy loamdrains and warms fast; dries out and needs more feeding
pH6.7neutral; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Lithnip-Hawkinspeak-Rock outcrop complex, 30 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 95646; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Kirkwood, CA

Summer high80 °Faverage high, July
Winter low18 °Faverage low, January
Hot days1days a year at 90 °F or more
Freezing nights222nights a year at 32 °F or less
Growing degree days1,093base 50 °F — the season’s usable heat
Longest day14 h 52 mindaylight on June 21
Shortest day9 h 28 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation42.7 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 43 °F, low 18 °F 43°18° JanFebruary: average high 43 °F, low 19 °F 43°19° FebMarch: average high 48 °F, low 24 °F 48°24° MarApril: average high 53 °F, low 28 °F 53°28° AprMay: average high 62 °F, low 33 °F 62°33° MayJune: average high 72 °F, low 38 °F 72°38° JunJuly: average high 80 °F, low 43 °F 80°43° JulAugust: average high 80 °F, low 41 °F 80°41° AugSeptember: average high 73 °F, low 35 °F 73°35° SepOctober: average high 62 °F, low 29 °F 62°29° OctNovember: average high 51 °F, low 23 °F 51°23° NovDecember: average high 43 °F, low 18 °F 43°18° Dec

Precipitation by month inches

0″2″4″6″8″January: 6.96 in precipitation 7.0 JanFebruary: 7.16 in precipitation 7.2 FebMarch: 6.61 in precipitation 6.6 MarApril: 3.50 in precipitation 3.5 AprMay: 2.44 in precipitation 2.4 MayJune: 0.64 in precipitation 0.6 JunJuly: 0.30 in precipitation 0.3 JulAugust: 0.43 in precipitation 0.4 AugSeptember: 0.67 in precipitation 0.7 SepOctober: 2.71 in precipitation 2.7 OctNovember: 4.49 in precipitation 4.5 NovDecember: 6.79 in precipitation 6.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: South Lake Tahoe Airport, CA (19 mi away); precipitation: Carson Pass, CA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

956447a
Kit Carson, CA · 6 mi
961557a
South Lake Tahoe, CA · 10 mi
961206b
Markleeville, CA · 11 mi
957217a
Echo Lake, CA · 13 mi
957357a
Twin Bridges, CA · 16 mi
961546b
South Lake Tahoe, CA · 17 mi
952236b
Arnold, CA · 17 mi
961506b
South Lake Tahoe, CA · 17 mi

California planting zones →

Questions about 95646

What planting zone is ZIP code 95646?

ZIP code 95646 (Kirkwood, CA) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Kirkwood, CA?

The median last spring frost (32 °F) near 95646 is June 7; after June 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Dagget Pass station.

When is the first frost in Kirkwood, CA?

The median first fall frost near 95646 is September 28, giving a median frost-free growing season of 113 days.

When should I plant tomatoes in 95646?

Start tomato seeds indoors around Apr 12 – Apr 26 and set transplants outside around Jun 14 – Jun 28, one to three weeks after the median last frost.

How much rain and snow does 95646 get?

About 42.7 inches of precipitation a year (NOAA 1991–2020 normals, Carson Pass station).

How hot do summers get in Kirkwood, CA?

The average high peaks at 80 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 95646 have?

The USDA soil survey maps Lithnip at the center of ZIP 95646: extremely gravelly sandy loam, somewhat excessively drained, pH about 6.7 (neutral).

Did spring come early in Kirkwood, CA in 2026?

Spring leaf-out near 95646 came on Mar 22 in 2026, 50 days earlier than the 1991–2020 average (May 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Kirkwood, CA?

Intermediate onions: the longest day near 95646 is 14 h 52 min, so day-neutral types bulb best; long-day varieties may not bulb fully.