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

Planting zone for 92539 — Anza, CA

ZIP code 92539 (Anza, Riverside County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 29 and the first fall frost November 18.

Where ZIP 92539 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 frostApr 29
First frostNov 18
2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Anza, 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 Anza, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 29median — 50% chance of a later frost
Safe for tender plantsMay 29only 10% chance of frost after
First fall frostNovember 18median — 10% chance by Oct 27
Growing season201 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around December 6.

From the NOAA station Palomar Mtn Obsy, CA — 15 miles away, elevation 5,551 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 92539

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 18 – Apr 1
SpinachSow outdoors · Mar 18 – Apr 8
Broccoli, cabbageStart indoors · Feb 18 – Mar 4
Broccoli, cabbageTransplant · Apr 8 – Apr 22
Onion setsPlant outdoors · Apr 1 – Apr 15
PotatoesPlant outdoors · Apr 8 – Apr 22
LettuceSow outdoors · Apr 1 – Apr 15
Carrots, beetsSow outdoors · Apr 8 – Apr 22
TomatoesStart indoors · Mar 4 – Mar 18
TomatoesTransplant · May 6 – May 20
Peppers, eggplantStart indoors · Feb 18 – Mar 4
Peppers, eggplantTransplant · May 13 – May 27
BeansSow outdoors · May 6 – May 20
Sweet cornSow outdoors · May 6 – May 20
Cucumbers, squashSow outdoors · May 6 – May 20
Fall lettuce, spinachSow outdoors · Sep 23 – Oct 7
GarlicPlant cloves · Nov 4 – Dec 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Nov 18) 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 92539 came on Jan 28 — 9 days earlier than the 1991–2020 average (Feb 6).

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 Anza, CA

The soil mapped at the center of ZIP 92539 is Bull Trail — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH6.1slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Bull Trail sandy loam, 8 to 15 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 92539; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Anza, CA

Summer high84 °Faverage high, July
Winter low36 °Faverage low, February
Hot days10days a year at 90 °F or more
Freezing nights49nights a year at 32 °F or less
Growing degree days3,690base 50 °F — the season’s usable heat
Longest day14 h 23 mindaylight on June 21
Shortest day9 h 56 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

30°40°50°60°70°80°90°32 °FJanuary: average high 51 °F, low 37 °F 51°37° JanFebruary: average high 51 °F, low 36 °F 51°36° FebMarch: average high 56 °F, low 39 °F 56°39° MarApril: average high 61 °F, low 42 °F 61°42° AprMay: average high 69 °F, low 48 °F 69°48° MayJune: average high 79 °F, low 57 °F 79°57° JunJuly: average high 84 °F, low 64 °F 84°64° JulAugust: average high 84 °F, low 65 °F 84°65° AugSeptember: average high 79 °F, low 60 °F 79°60° SepOctober: average high 69 °F, low 51 °F 69°51° OctNovember: average high 58 °F, low 43 °F 58°43° NovDecember: average high 51 °F, low 37 °F 51°37° 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: Palomar Mtn Obsy, CA (15 mi away); precipitation: Anza, CA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

925618b
Mountain Center, CA · 8 mi
925369b
Aguanga, CA · 10 mi
920868b
Warner Springs, CA · 15 mi
9226410a
Palm Springs, CA · 15 mi
925449b
Hemet, CA · 16 mi
9226110a
Palm Desert, CA · 17 mi
9226310a
Palm Springs, CA · 17 mi
920609a
Palomar Mountain, CA · 18 mi

California planting zones →

Questions about 92539

What planting zone is ZIP code 92539?

ZIP code 92539 (Anza, 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 Anza, CA?

The median last spring frost (32 °F) near 92539 is April 29; after May 29 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Palomar Mtn Obsy station.

When is the first frost in Anza, CA?

The median first fall frost near 92539 is November 18, giving a median frost-free growing season of 201 days.

When should I plant tomatoes in 92539?

Start tomato seeds indoors around Mar 4 – Mar 18 and set transplants outside around May 6 – May 20, one to three weeks after the median last frost.

How much rain and snow does 92539 get?

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

How hot do summers get in Anza, CA?

The average high peaks at 84 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 92539 have?

The USDA soil survey maps Bull Trail at the center of ZIP 92539: sandy loam, well drained, pH about 6.1 (slightly acidic).

Did spring come early in Anza, CA in 2026?

Spring leaf-out near 92539 came on Jan 28 in 2026, 9 days earlier than the 1991–2020 average (Feb 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Anza, CA?

Intermediate onions: the longest day near 92539 is 14 h 23 min, so day-neutral types bulb best; long-day varieties may not bulb fully.