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

Planting zone for 95642 — Jackson, CA

ZIP code 95642 (Jackson, Amador County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is March 4 and the first fall frost December 11.

Where ZIP 95642 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 frostMar 4
First frostDec 11
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 Jackson, 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 Jackson, 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 frostDecember 11median — 10% chance by Nov 19
Growing season285 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 10 and returns around December 27.

From the NOAA station Sutter Hill Cdf, CA — 3 miles away, elevation 1,585 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 95642

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 · Oct 16 – Oct 30
GarlicPlant cloves · Nov 27 – Jan 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 4) and first fall frost (Dec 11) 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 95642 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 Jackson, CA

The center of ZIP 95642 is mapped as Loamy alluvial land: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 95642; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Jackson, CA

Summer high93 °Faverage high, July
Winter low39 °Faverage low, January
Hot days75days a year at 90 °F or more
Freezing nights15nights a year at 32 °F or less
Growing degree days4,486base 50 °F — the season’s usable heat
Longest day14 h 50 mindaylight on June 21
Shortest day9 h 29 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation32 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 39 °F 55°39° JanFebruary: average high 58 °F, low 42 °F 58°42° FebMarch: average high 62 °F, low 42 °F 62°42° MarApril: average high 67 °F, low 45 °F 67°45° AprMay: average high 75 °F, low 51 °F 75°51° MayJune: average high 86 °F, low 57 °F 86°57° JunJuly: average high 93 °F, low 63 °F 93°63° JulAugust: average high 92 °F, low 62 °F 92°62° AugSeptember: average high 87 °F, low 60 °F 87°60° SepOctober: average high 77 °F, low 53 °F 77°53° OctNovember: average high 63 °F, low 44 °F 63°44° NovDecember: average high 55 °F, low 39 °F 55°39° Dec

Precipitation by month inches

0″2″4″6″January: 6.06 in precipitation 6.1 JanFebruary: 5.66 in precipitation 5.7 FebMarch: 4.90 in precipitation 4.9 MarApril: 2.78 in precipitation 2.8 AprMay: 1.69 in precipitation 1.7 MayJune: 0.38 in precipitation 0.4 JunJuly: 0.02 in precipitation 0.0 JulAugust: 0.04 in precipitation 0.0 AugSeptember: 0.26 in precipitation 0.3 SepOctober: 1.71 in precipitation 1.7 OctNovember: 3.12 in precipitation 3.1 NovDecember: 5.40 in precipitation 5.4 Dec

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

Nearby ZIP codes

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

956549b
Martell, CA · <1 mi
956859a
Sutter Creek, CA · 6 mi
956019b
Amador City, CA · 7 mi
956659a
Pine Grove, CA · 7 mi
956999b
Drytown, CA · 8 mi
952459a
Mokelumne Hill, CA · 9 mi
952269b
Campo Seco, CA · 9 mi
956409b
Ione, CA · 10 mi

California planting zones →

Questions about 95642

What planting zone is ZIP code 95642?

ZIP code 95642 (Jackson, 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 Jackson, CA?

The median last spring frost (32 °F) near 95642 is March 4; after April 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sutter Hill Cdf station.

When is the first frost in Jackson, CA?

The median first fall frost near 95642 is December 11, giving a median frost-free growing season of 285 days.

When should I plant tomatoes in 95642?

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 95642 get?

About 32 inches of precipitation a year (NOAA 1991–2020 normals, Sutter Hill Cdf station).

How hot do summers get in Jackson, CA?

The average high peaks at 93 °F in July, with about 75 days a year at 90 °F or more.

Did spring come early in Jackson, CA in 2026?

Spring leaf-out near 95642 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 Jackson, CA?

Intermediate onions: the longest day near 95642 is 14 h 50 min, so day-neutral types bulb best; long-day varieties may not bulb fully.