Zone 10a · Last frost ~Feb 2 · Soil 72.1°F today (measured) · See your place on the 2023 USDA zone map
This ZIP is part of Poway & San Diego, where nearby ZIPs share the same stations and zone. That page compares every ZIP in the area.
Public NOAA/USDA data, updated 2026-10-16 19:24 UTC.
USDA Plant Hardiness Zone Map · San Diego focus
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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
10a
USDA 2023 · 30 to 35°F
Last frost
Feb 2
avg last frost (50%)
Soil temp Measured
72.1°F
↓ 14.7° in 7 days
Chill hours
—
starts Nov 1
Rain
1.02″
since Oct 1 · normal 0.19″
Frost dates for 92128
Last spring frost
Feb 2
50% odds
First fall frost
Dec 7
50% odds
Safer spring date
Mar 4
10% chance of later frost
Growing season
309
days (50%)
Earliest-risk fall date (10%): Nov 22.
Station record: 19 of the 30 years in 1991–2020, which NOAA still uses for freeze dates. A full record would be more reliable.
NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal freeze probabilities (32F) · CA SAN PASQUAL ANIMAL PK (USC00047874) 11.9 km away 19 yrs of record · 325 ft lower than this ZIP
Newsletter · 92128
Frost alerts and planting reminders for 92128. Coming soon.
Ad strip · leaderboard 970×90 / 728×90
7-day forecast · High / Low / Rain / Frost / Wind
High wind: 1 day(s) with gusts ≥40 mph. Stake and protect transplants.
Fri 16
90°72°gust 49 mph💧2%
High wind
Sat 17
86°64°gust 36 mph💧2%
Clear
Sun 18
86°62°gust 17 mph💧1%
Clear
Mon 19
81°61°gust 16 mph💧9%
Clear
Tue 20
72°58°gust 25 mph💧64% · 0.04″
Rain
Wed 21
69°56°gust 21 mph💧64% · 0.50″
Rain
Thu 22
68°55°gust 18 mph💧32% · 0.10″
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 · 92128
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.
ZIP 92128 (San Diego, CA) is in USDA zone 10a (30 to 35°F average annual extreme minimum), per the 2023 USDA Plant Hardiness Zone Map.
When is the last frost in 92128?
Based on NOAA 1991–2020 normals at Ca San Pasqual Animal Pk (11.9 km away), the median last 32°F freeze is Feb 2. In 1 of 10 years it is after Mar 4. The median first fall freeze is Dec 7.
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 SAN PASQUAL ANIMAL PK (USC00047874) 11.9 km away 19 yrs of record · 325 ft lower than this ZIP
Forecast: NOAA National Weather Service api.weather.gov (7-day forecast + gridpoint wind gusts)
Soil: NOAA U.S. Climate Reference Network (USCRN) hourly02, SOIL_TEMP_10
Chill: CIMIS, California Department of Water Resources (hourly air temperature; QC-flagged hours dropped)
