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

Planting zone for 92583 — San Jacinto, CA

ZIP code 92583 (San Jacinto, Riverside County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is January 31 and the first fall frost December 10.

Where ZIP 92583 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 frostJan 31
First frostDec 10
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 San Jacinto, 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 San Jacinto, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 31median — 50% chance of a later frost
Safe for tender plantsFebruary 28only 10% chance of frost after
First fall frostDecember 10median — 10% chance by Nov 22
Growing season315 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 3 and returns around December 21.

From the NOAA station San Jacinto, CA — 2 miles away, elevation 1,526 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 92583

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 20 – Jan 3
SpinachSow outdoors · Dec 20 – Jan 10
Broccoli, cabbageStart indoors · Nov 22 – Dec 6
Broccoli, cabbageTransplant · Jan 10 – Jan 24
Onion setsPlant outdoors · Jan 3 – Jan 17
PotatoesPlant outdoors · Jan 10 – Jan 24
LettuceSow outdoors · Jan 3 – Jan 17
Carrots, beetsSow outdoors · Jan 10 – Jan 24
TomatoesStart indoors · Dec 6 – Dec 20
TomatoesTransplant · Feb 7 – Feb 21
Peppers, eggplantStart indoors · Nov 22 – Dec 6
Peppers, eggplantTransplant · Feb 14 – Feb 28
BeansSow outdoors · Feb 7 – Feb 21
Sweet cornSow outdoors · Feb 7 – Feb 21
Cucumbers, squashSow outdoors · Feb 7 – Feb 21
Fall lettuce, spinachSow outdoors · Oct 15 – Oct 29
GarlicPlant cloves · Nov 26 – Dec 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 31) and first fall frost (Dec 10) 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 92583 came on Jan 18 — 7 days earlier than the 1991–2020 average (Jan 25).

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 San Jacinto, CA

The soil mapped at the center of ZIP 92583 is San Emigdio — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH8.2alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: San Emigdio fine sandy loam, 2 to 8 percent slopes, eroded.

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 92583; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Jacinto, CA

Summer high97 °Faverage high, August
Winter low39 °Faverage low, December
Hot days120days a year at 90 °F or more
Freezing nights15nights a year at 32 °F or less
Growing degree days5,606base 50 °F — the season’s usable heat
Longest day14 h 24 mindaylight on June 21
Shortest day9 h 54 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation12.2 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 66 °F, low 40 °F 66°40° JanFebruary: average high 66 °F, low 42 °F 66°42° FebMarch: average high 70 °F, low 45 °F 70°45° MarApril: average high 74 °F, low 48 °F 74°48° AprMay: average high 80 °F, low 53 °F 80°53° MayJune: average high 89 °F, low 58 °F 89°58° JunJuly: average high 95 °F, low 64 °F 95°64° JulAugust: average high 97 °F, low 64 °F 97°64° AugSeptember: average high 92 °F, low 61 °F 92°61° SepOctober: average high 82 °F, low 53 °F 82°53° OctNovember: average high 73 °F, low 44 °F 73°44° NovDecember: average high 65 °F, low 39 °F 65°39° Dec

Precipitation by month inches

0″1″2″3″January: 2.66 in precipitation 2.7 JanFebruary: 2.76 in precipitation 2.8 FebMarch: 1.69 in precipitation 1.7 MarApril: 0.79 in precipitation 0.8 AprMay: 0.47 in precipitation 0.5 MayJune: 0.07 in precipitation 0.1 JunJuly: 0.20 in precipitation 0.2 JulAugust: 0.12 in precipitation 0.1 AugSeptember: 0.26 in precipitation 0.3 SepOctober: 0.54 in precipitation 0.5 OctNovember: 0.77 in precipitation 0.8 NovDecember: 1.87 in precipitation 1.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: San Jacinto, CA (2 mi away); precipitation: San Jacinto, CA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

925819b
San Jacinto, CA · 2 mi
925469b
Hemet, CA · 4 mi
925829b
San Jacinto, CA · 5 mi
925439b
Hemet, CA · 7 mi
925459b
Hemet, CA · 8 mi
925679b
Nuevo, CA · 9 mi
922239b
Beaumont, CA · 10 mi
925489b
Homeland, CA · 10 mi

All 3 ZIP codes in San Jacinto → · California planting zones →

Questions about 92583

What planting zone is ZIP code 92583?

ZIP code 92583 (San Jacinto, 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 San Jacinto, CA?

The median last spring frost (32 °F) near 92583 is January 31; after February 28 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, San Jacinto station.

When is the first frost in San Jacinto, CA?

The median first fall frost near 92583 is December 10, giving a median frost-free growing season of 315 days.

When should I plant tomatoes in 92583?

Start tomato seeds indoors around Dec 6 – Dec 20 and set transplants outside around Feb 7 – Feb 21, one to three weeks after the median last frost.

How much rain and snow does 92583 get?

About 12.2 inches of precipitation a year (NOAA 1991–2020 normals, San Jacinto station).

How hot do summers get in San Jacinto, CA?

The average high peaks at 97 °F in August, with about 120 days a year at 90 °F or more.

What kind of soil does 92583 have?

The USDA soil survey maps San Emigdio at the center of ZIP 92583: fine sandy loam, well drained, pH about 8.2 (alkaline).

Did spring come early in San Jacinto, CA in 2026?

Spring leaf-out near 92583 came on Jan 18 in 2026, 7 days earlier than the 1991–2020 average (Jan 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in San Jacinto, CA?

Intermediate onions: the longest day near 92583 is 14 h 24 min, so day-neutral types bulb best; long-day varieties may not bulb fully.