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

Planting zone for 92561 — Mountain Center, CA

ZIP code 92561 (Mountain Center, Riverside County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is May 16 and the first fall frost October 24.

Where ZIP 92561 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.

Zone8b15 to 20 °F
Coldest night−9.4 to −6.7 °C
Last frostMay 16
First frostOct 24
2012 zone8a

Was 8a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mountain Center, 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 Mountain Center, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 16median — 50% chance of a later frost
Safe for tender plantsJune 5only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 1
Growing season160 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 24 and returns around November 10.

From the NOAA station Idyllwild Fire Dept, CA — 11 miles away, elevation 5,381 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 92561

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 4 – Apr 18
SpinachSow outdoors · Apr 4 – Apr 25
Broccoli, cabbageStart indoors · Mar 7 – Mar 21
Broccoli, cabbageTransplant · Apr 25 – May 9
Onion setsPlant outdoors · Apr 18 – May 2
PotatoesPlant outdoors · Apr 25 – May 9
LettuceSow outdoors · Apr 18 – May 2
Carrots, beetsSow outdoors · Apr 25 – May 9
TomatoesStart indoors · Mar 21 – Apr 4
TomatoesTransplant · May 23 – Jun 6
Peppers, eggplantStart indoors · Mar 7 – Mar 21
Peppers, eggplantTransplant · May 30 – Jun 13
BeansSow outdoors · May 23 – Jun 6
Sweet cornSow outdoors · May 23 – Jun 6
Cucumbers, squashSow outdoors · May 23 – Jun 6
Fall lettuce, spinachSow outdoors · Aug 29 – Sep 12
GarlicPlant cloves · Oct 10 – Nov 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 16) and first fall frost (Oct 24) 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 92561 came on Feb 3 — 18 days earlier than the 1991–2020 average (Feb 21).

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 Mountain Center, CA

The center of ZIP 92561 is mapped as Rock outcrop, 30 to 100 percent slopes: 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 92561; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mountain Center, CA

Summer high86 °Faverage high, August
Winter low30 °Faverage low, February
Hot days18days a year at 90 °F or more
Freezing nights107nights a year at 32 °F or less
Growing degree days2,838base 50 °F — the season’s usable heat
Longest day14 h 23 mindaylight on June 21
Shortest day9 h 55 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation10.6 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 55 °F, low 31 °F 55°31° JanFebruary: average high 55 °F, low 30 °F 55°30° FebMarch: average high 59 °F, low 32 °F 59°32° MarApril: average high 64 °F, low 35 °F 64°35° AprMay: average high 71 °F, low 41 °F 71°41° MayJune: average high 80 °F, low 48 °F 80°48° JunJuly: average high 85 °F, low 55 °F 85°55° JulAugust: average high 86 °F, low 55 °F 86°55° AugSeptember: average high 81 °F, low 50 °F 81°50° SepOctober: average high 72 °F, low 42 °F 72°42° OctNovember: average high 62 °F, low 35 °F 62°35° NovDecember: average high 54 °F, low 30 °F 54°30° Dec

Precipitation by month inches

0″1″2″3″January: 1.79 in precipitation 1.8 JanFebruary: 2.19 in precipitation 2.2 FebMarch: 1.35 in precipitation 1.4 MarApril: 0.75 in precipitation 0.8 AprMay: 0.39 in precipitation 0.4 MayJune: 0.08 in precipitation 0.1 JunJuly: 0.39 in precipitation 0.4 JulAugust: 0.21 in precipitation 0.2 AugSeptember: 0.47 in precipitation 0.5 SepOctober: 0.68 in precipitation 0.7 OctNovember: 1.14 in precipitation 1.1 NovDecember: 1.14 in precipitation 1.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Idyllwild Fire Dept, CA (11 mi away); precipitation: Anza, CA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

9226410a
Palm Springs, CA · 8 mi
925398b
Anza, CA · 8 mi
9226310a
Palm Springs, CA · 9 mi
9226110a
Palm Desert, CA · 10 mi
9226010a
Palm Desert, CA · 11 mi
9223510a
Cathedral City, CA · 12 mi
9227010a
Rancho Mirage, CA · 13 mi
925498a
Idyllwild, CA · 13 mi

California planting zones →

Questions about 92561

What planting zone is ZIP code 92561?

ZIP code 92561 (Mountain Center, CA) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Mountain Center, CA?

The median last spring frost (32 °F) near 92561 is May 16; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Idyllwild Fire Dept station.

When is the first frost in Mountain Center, CA?

The median first fall frost near 92561 is October 24, giving a median frost-free growing season of 160 days.

When should I plant tomatoes in 92561?

Start tomato seeds indoors around Mar 21 – Apr 4 and set transplants outside around May 23 – Jun 6, one to three weeks after the median last frost.

How much rain and snow does 92561 get?

About 10.6 inches of precipitation a year (NOAA 1991–2020 normals, Anza station).

How hot do summers get in Mountain Center, CA?

The average high peaks at 86 °F in August, with about 18 days a year at 90 °F or more.

Did spring come early in Mountain Center, CA in 2026?

Spring leaf-out near 92561 came on Feb 3 in 2026, 18 days earlier than the 1991–2020 average (Feb 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mountain Center, CA?

Intermediate onions: the longest day near 92561 is 14 h 23 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 92561 change?

Yes. The 2012 USDA map put 92561 in zone 8a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.