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

Planting zone for 92522 — Riverside, CA

ZIP code 92522 (Riverside, Riverside County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 92522 is

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.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostrare
First frostrare
2012 zone9b

Was 9b 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 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Riverside, 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

A 32 °F frost doesn't happen here in most winters. At the nearest station (NOAA station Riverside Fire Stn 3, CA — within 1 mile, elevation 840 ft) the median growing season is 353 days. When frost does come, it is a midwinter night or two; cover tender plants when a freeze is forecast.

Frost data: NOAA NCEI U.S. Climate Normals 1991–2020.

When spring arrived in 2026

In 2026, spring leaf-out near 92522 came on Jan 17 — 6 days earlier than the 1991–2020 average (Jan 23).

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 Riverside, CA

The soil mapped at the center of ZIP 92522 is Arlington — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Arlington fine sandy loam, deep, 0 to 2 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 92522; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Riverside, CA

Summer high97 °Faverage high, August
Winter low42 °Faverage low, December
Hot days110days a year at 90 °F or more
Freezing nights2nights a year at 32 °F or less
Growing degree days6,222base 50 °F — the season’s usable heat
Longest day14 h 25 mindaylight on June 21
Shortest day9 h 53 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation10 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 70 °F, low 43 °F 70°43° JanFebruary: average high 70 °F, low 44 °F 70°44° FebMarch: average high 73 °F, low 46 °F 73°46° MarApril: average high 78 °F, low 50 °F 78°50° AprMay: average high 81 °F, low 55 °F 81°55° MayJune: average high 89 °F, low 59 °F 89°59° JunJuly: average high 95 °F, low 64 °F 95°64° JulAugust: average high 97 °F, low 65 °F 97°65° AugSeptember: average high 93 °F, low 62 °F 93°62° SepOctober: average high 84 °F, low 55 °F 84°55° OctNovember: average high 76 °F, low 47 °F 76°47° NovDecember: average high 69 °F, low 42 °F 69°42° Dec

Precipitation by month inches

0″1″2″3″January: 2.19 in precipitation 2.2 JanFebruary: 2.47 in precipitation 2.5 FebMarch: 1.58 in precipitation 1.6 MarApril: 0.58 in precipitation 0.6 AprMay: 0.20 in precipitation 0.2 MayJune: 0.08 in precipitation 0.1 JunJuly: 0.12 in precipitation 0.1 JulAugust: 0.13 in precipitation 0.1 AugSeptember: 0.15 in precipitation 0.1 SepOctober: 0.44 in precipitation 0.4 OctNovember: 0.68 in precipitation 0.7 NovDecember: 1.40 in precipitation 1.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Riverside Fire Stn 3, CA (within 1 mile); precipitation: Riverside Fire Stn 3, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10a.

9250210a
Riverside, CA · <1 mi
9251310a
Riverside, CA · <1 mi
9251410a
Riverside, CA · <1 mi
9251610a
Riverside, CA · <1 mi
9251710a
Riverside, CA · <1 mi
9251910a
Riverside, CA · <1 mi
9250610a
Riverside, CA · 2 mi
9250410a
Riverside, CA · 3 mi

All 16 ZIP codes in Riverside → · California planting zones →

Questions about 92522

What planting zone is ZIP code 92522?

ZIP code 92522 (Riverside, CA) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

How much rain and snow does 92522 get?

About 10 inches of precipitation a year (NOAA 1991–2020 normals, Riverside Fire Stn 3 station).

How hot do summers get in Riverside, CA?

The average high peaks at 97 °F in August, with about 110 days a year at 90 °F or more.

What kind of soil does 92522 have?

The USDA soil survey maps Arlington at the center of ZIP 92522: fine sandy loam, well drained, pH about 7.0 (neutral).

Did spring come early in Riverside, CA in 2026?

Spring leaf-out near 92522 came on Jan 17 in 2026, 6 days earlier than the 1991–2020 average (Jan 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Riverside, CA?

Intermediate onions: the longest day near 92522 is 14 h 25 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 92522 change?

Yes. The 2012 USDA map put 92522 in zone 9b; the 2023 map puts it in zone 10a. The newer map uses 1991–2020 data and more weather stations.