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

Planting zone for 91913 — Chula Vista, CA

ZIP code 91913 (Chula Vista, San Diego County) is in USDA zone 10b: the coldest winter night averages 35 to 40 °F.

Where ZIP 91913 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.

Zone10b35 to 40 °F
Coldest night1.7 to 4.4 °C
Last frostrare
First frostrare
2012 zone10a

Was 10a 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 10b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Chula Vista, 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 San Diego Brown Field, CA — 4 miles away, elevation 515 ft) the median growing season is 365 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 91913 came on Jan 18 — 3 days earlier than 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 Chula Vista, CA

The soil mapped at the center of ZIP 91913 is Diablo — clay, well drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Diablo clay, 2 to 9 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 91913; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Chula Vista, CA

Summer high81 °Faverage high, August
Winter low44 °Faverage low, January
Hot days13days a year at 90 °F or more
Freezing nights1nights a year at 32 °F or less
Growing degree days4,638base 50 °F — the season’s usable heat
Longest day14 h 18 mindaylight on June 21
Shortest day10 h 00 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation12.2 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°32 °FJanuary: average high 67 °F, low 44 °F 67°44° JanFebruary: average high 66 °F, low 45 °F 66°45° FebMarch: average high 68 °F, low 47 °F 68°47° MarApril: average high 70 °F, low 50 °F 70°50° AprMay: average high 71 °F, low 54 °F 71°54° MayJune: average high 74 °F, low 58 °F 74°58° JunJuly: average high 78 °F, low 62 °F 78°62° JulAugust: average high 81 °F, low 63 °F 81°63° AugSeptember: average high 80 °F, low 61 °F 80°61° SepOctober: average high 77 °F, low 55 °F 77°55° OctNovember: average high 72 °F, low 49 °F 72°49° NovDecember: average high 67 °F, low 44 °F 67°44° Dec

Precipitation by month inches

0″1″2″3″January: 2.57 in precipitation 2.6 JanFebruary: 2.87 in precipitation 2.9 FebMarch: 1.85 in precipitation 1.9 MarApril: 0.79 in precipitation 0.8 AprMay: 0.37 in precipitation 0.4 MayJune: 0.08 in precipitation 0.1 JunJuly: 0.08 in precipitation 0.1 JulAugust: 0.03 in precipitation 0.0 AugSeptember: 0.17 in precipitation 0.2 SepOctober: 0.52 in precipitation 0.5 OctNovember: 1.04 in precipitation 1.0 NovDecember: 1.82 in precipitation 1.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: San Diego Brown Field, CA (4 mi away); precipitation: Chula Vista 6.3e, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10b.

9191510b
Chula Vista, CA · 2 mi
9215410b
San Diego, CA · 3 mi
9190810b
Bonita, CA · 3 mi
9191410b
Chula Vista, CA · 4 mi
9190210b
Bonita, CA · 4 mi
9191110b
Chula Vista, CA · 4 mi
9217910b
San Diego, CA · 4 mi
9191010b
Chula Vista, CA · 4 mi

All 8 ZIP codes in Chula Vista → · California planting zones →

Questions about 91913

What planting zone is ZIP code 91913?

ZIP code 91913 (Chula Vista, CA) is in USDA hardiness zone 10b on the 2023 map: the coldest night of an average winter reaches 35 to 40 °F (1.7 to 4.4 °C).

How much rain and snow does 91913 get?

About 12.2 inches of precipitation a year (NOAA 1991–2020 normals, Chula Vista 6.3e station).

How hot do summers get in Chula Vista, CA?

The average high peaks at 81 °F in August, with about 13 days a year at 90 °F or more.

What kind of soil does 91913 have?

The USDA soil survey maps Diablo at the center of ZIP 91913: clay, well drained, pH about 7.2 (neutral).

Did spring come early in Chula Vista, CA in 2026?

Spring leaf-out near 91913 came on Jan 18 in 2026, 3 days earlier than the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Chula Vista, CA?

Short-day onions: the longest day near 91913 is 14 h 18 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 91913 change?

Yes. The 2012 USDA map put 91913 in zone 10a; the 2023 map puts it in zone 10b. The newer map uses 1991–2020 data and more weather stations.