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

Planting zone for 92250 — Holtville, CA

ZIP code 92250 (Holtville, Imperial County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 92250 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.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostrare
First frostrare
2012 zone10a

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 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Holtville, 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 El Centro 2 Ssw, CA — 25 miles away, elevation -30 ft) the median growing season is 363 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 92250 came on Jan 19 — about the same time as the 1991–2020 average (Jan 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 Holtville, CA

The soil mapped at the center of ZIP 92250 is Rositas — fine sand, somewhat excessively drained.

TextureFine sanddrains and warms fast; dries out and needs more feeding
pH8.0alkaline; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter0.2%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Rositas fine sand, 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 92250; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Holtville, CA

Summer high107 °Faverage high, July
Winter low43 °Faverage low, January
Hot days180days a year at 90 °F or more
Freezing nights1nights a year at 32 °F or less
Growing degree days8,902base 50 °F — the season’s usable heat
Longest day14 h 19 mindaylight on June 21
Shortest day9 h 59 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation2.5 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°120°32 °FJanuary: average high 71 °F, low 43 °F 71°43° JanFebruary: average high 74 °F, low 47 °F 74°47° FebMarch: average high 80 °F, low 52 °F 80°52° MarApril: average high 86 °F, low 57 °F 86°57° AprMay: average high 94 °F, low 63 °F 94°63° MayJune: average high 103 °F, low 71 °F 103°71° JunJuly: average high 107 °F, low 78 °F 107°78° JulAugust: average high 107 °F, low 79 °F 107°79° AugSeptember: average high 102 °F, low 73 °F 102°73° SepOctober: average high 92 °F, low 62 °F 92°62° OctNovember: average high 79 °F, low 51 °F 79°51° NovDecember: average high 70 °F, low 43 °F 70°43° Dec

Precipitation by month inches

0″1″January: 0.41 in precipitation 0.4 JanFebruary: 0.34 in precipitation 0.3 FebMarch: 0.22 in precipitation 0.2 MarApril: 0.06 in precipitation 0.1 AprMay: 0.01 in precipitation 0.0 MayJune: 0.00 in precipitation 0.0 JunJuly: 0.18 in precipitation 0.2 JulAugust: 0.24 in precipitation 0.2 AugSeptember: 0.19 in precipitation 0.2 SepOctober: 0.26 in precipitation 0.3 OctNovember: 0.23 in precipitation 0.2 NovDecember: 0.35 in precipitation 0.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: El Centro 2 Ssw, CA (25 mi away); precipitation: Calexico 2 Ne, CA (20 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10a.

9222710a
Brawley, CA · 19 mi
9224910a
Heber, CA · 21 mi
9228310a
Winterhaven, CA · 22 mi
9223210a
Calexico, CA · 23 mi
9223110a
Calexico, CA · 26 mi
9224310a
El Centro, CA · 27 mi
8536410a
Yuma, AZ · 28 mi
8535010a
Somerton, AZ · 29 mi

California planting zones →

Questions about 92250

What planting zone is ZIP code 92250?

ZIP code 92250 (Holtville, 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 92250 get?

About 2.5 inches of precipitation a year (NOAA 1991–2020 normals, Calexico 2 Ne station).

How hot do summers get in Holtville, CA?

The average high peaks at 107 °F in July, with about 180 days a year at 90 °F or more.

What kind of soil does 92250 have?

The USDA soil survey maps Rositas at the center of ZIP 92250: fine sand, somewhat excessively drained, pH about 8.0 (alkaline).

Did spring come early in Holtville, CA in 2026?

Spring leaf-out near 92250 came on Jan 19 in 2026, about the same as the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Holtville, CA?

Intermediate onions: the longest day near 92250 is 14 h 19 min, so day-neutral types bulb best; long-day varieties may not bulb fully.