Garden Climate for Potrero, CA 91963

Zone 9a · Last frost ~Apr 30 · Soil 63.9°F today (modeled) · See your place on the 2023 USDA zone map

Public NOAA/USDA data, updated 2026-10-16 18:57 UTC.

USDA Plant Hardiness Zone Map · Potrero focus

2023 USDA Plant Hardiness Zone Map around ZIP 91963, marker at Potrero, CA
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USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture. Accessed from https://planthardiness.ars.usda.gov/. Rendered unaltered from the PRISM Group, Oregon State University GIS data (https://prism.oregonstate.edu, accessed 15 Oct 2026) with official zone colors. Roads (TIGER/Line 2023 primary roads), place names (2023 Gazetteer) and state lines (2023 cartographic boundaries 1:500k) are drawn on top. Source: U.S. Census Bureau.

Zone
9a
USDA 2023 · 20 to 25°F
Last frost
Apr 30
avg last frost (50%)
Soil temp Modeled
63.9°F
↓ 11.2° in 7 days
Chill hours
—
unavailable
Rain
2.32″
since Oct 1 · normal 0.20″

Frost dates for 91963

Last spring frost
Apr 30
50% odds
First fall frost
Oct 26
50% odds
Safer spring date
Jun 1
10% chance of later frost
Growing season
174
days (50%)

Earliest-risk fall date (10%): Sep 30.

NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal freeze probabilities (32F) · CA CAMPO (USC00041424) 12.5 km away 27 yrs of record · 295 ft higher than this ZIP

Newsletter · 91963

Frost alerts and planting reminders for 91963. Coming soon.

Ad strip · leaderboard 970×90 / 728×90

7-day forecast · High / Low / Rain / Frost / Wind

High wind: 2 day(s) with gusts ≥40 mph. Stake and protect transplants.
Fri 16
77° 64° gust 59 mph 💧7%
High wind
Sat 17
73° 60° gust 46 mph 💧7%
High wind
Sun 18
76° 58° gust 23 mph 💧0%
Clear
Mon 19
75° 55° gust 17 mph 💧3%
Clear
Tue 20
65° 52° gust 38 mph 💧58% · 0.01″
Rain
Wed 21
60° 49° gust 31 mph 💧67% · 0.36″
Rain
Thu 22
61° 48° gust 21 mph 💧26% · 0.05″
Clear

NOAA NWS api.weather.gov (SGX). Frost = low ≤32°F · High wind = gust ≥40 mph · 💧 = chance of precipitation and expected amount (NWS quantitative precipitation forecast; blank when NWS gives none) · Rain = chance ≥50%.

What to grow when · 91963

Calendar: San Diego County, inland valleys (guide Regions 3-4). Planting months from UC Master Gardeners of San Diego County; Master Gardener Association of San Diego County. Harvest months add typical days-to-harvest. This month also checks live soil temperature and the 7-day frost forecast. The harvest planner uses the same calendar. Rules: methodology.

Affiliate links (disclosed). Placeholders, no partners yet:Frost clothSoil thermometer

Questions about 91963

What USDA hardiness zone is 91963?

ZIP 91963 (Potrero, CA) is in USDA zone 9a (20 to 25°F average annual extreme minimum), per the 2023 USDA Plant Hardiness Zone Map.

When is the last frost in 91963?

Based on NOAA 1991–2020 normals at Ca Campo (12.5 km away), the median last 32°F freeze is Apr 30. In 1 of 10 years it is after Jun 1. The median first fall freeze is Oct 26.

Nearby ZIP codes

91980 Tecate 91906 Campo 91917 Dulzura 91935 Jamul 91931 Guatay 91901 Alpine

Sources for this page

  • Location: US Census Bureau 2023 Gazetteer, ZCTA internal point
  • Zone: USDA Plant Hardiness Zone Map 2023, ZIP datasets (USDA ARS + PRISM Climate Group, Oregon State University)
  • Frost: NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal freeze probabilities (32F) CA CAMPO (USC00041424) 12.5 km away 27 yrs of record · 295 ft higher than this ZIP
  • Forecast: NOAA National Weather Service api.weather.gov (7-day forecast + gridpoint wind gusts)
  • Soil: Open-Meteo forecast API soil model (non-commercial terms)
  • Chill: RuntimeError: not enough nearby data: no hourly weather station within 40 km on the same side of the coastal/inland divide
  • Raw data: /data/zip/91963.json