Garden Climate for Descanso, CA 91916

Zone 9b · Last frost ~Apr 19 · Soil 62.4°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 · Descanso focus

2023 USDA Plant Hardiness Zone Map around ZIP 91916, marker at Descanso, CA
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The map pixel at the marker shows 9a. The ZIP lookup table gives 9b for the whole ZIP area. Zone edges run through or near this ZIP.

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
9b
USDA 2023 · 25 to 30°F
Last frost
Apr 19
avg last frost (50%)
Soil temp Modeled
62.4°F
↓ 7.8° in 7 days
Chill hours
—
unavailable
Rain
—
since Oct 1 · not enough data

Frost dates for 91916

Last spring frost
Apr 19
50% odds
First fall frost
Oct 27
50% odds
Safer spring date
May 14
10% chance of later frost
Growing season
190
days (50%)

Earliest-risk fall date (10%): Oct 9.

NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal freeze probabilities (32F) · CA CUYAMACA HCN (USC00042239) 13.1 km away 25 yrs of record · 650 ft higher than this ZIP

Newsletter · 91916

Frost alerts and planting reminders for 91916. 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
75° 62° gust 56 mph 💧10%
High wind
Sat 17
70° 57° gust 45 mph 💧10%
High wind
Sun 18
74° 58° gust 21 mph 💧0%
Clear
Mon 19
74° 54° gust 16 mph 💧5%
Clear
Tue 20
64° 50° gust 25 mph 💧60% · 0.03″
Rain
Wed 21
59° 48° gust 23 mph 💧71% · 0.71″
Rain
Thu 22
59° 47° gust 21 mph 💧30% · 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 · 91916

Calendar: San Diego County, mountains (900 m / ~3,000 ft and up). Planting months from University of Arizona Cooperative Extension Yavapai County Bulletin #51 'Yavapai County Vegetable Planting Dates' (an out-of-county analog; no San Diego-specific guide covers this area). 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 91916

What USDA hardiness zone is 91916?

ZIP 91916 (Descanso, CA) is in USDA zone 9b (25 to 30°F average annual extreme minimum), per the 2023 USDA Plant Hardiness Zone Map.

When is the last frost in 91916?

Based on NOAA 1991–2020 normals at Ca Cuyamaca Hcn (13.1 km away), the median last 32°F freeze is Apr 19. In 1 of 10 years it is after May 14. The median first fall freeze is Oct 27.

Nearby ZIP codes

91931 Guatay 91962 Pine Valley 91901 Alpine 91948 Mount Laguna 92065 Ramona 92021 El Cajon

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 CUYAMACA HCN (USC00042239) 13.1 km away 25 yrs of record · 650 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 suitable hourly weather station within 25 km
  • Raw data: /data/zip/91916.json