Garden Climate for Lemon Grove, CA 91945

Zone 10b · Frost-free in most years · Soil 71.3°F today (modeled) · See your place on the 2023 USDA zone map

This ZIP is part of La Mesa, Lemon Grove & Spring Valley, 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 · Lemon Grove focus

2023 USDA Plant Hardiness Zone Map around ZIP 91945, marker at Lemon Grove, 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
10b
USDA 2023 · 35 to 40°F
Last frost
None
frost-free ≥9 of 10 yrs
Soil temp Modeled
71.3°F
↓ 6.8° in 7 days
Chill hours
—
starts Nov 1
Rain
1.02″
since Oct 1 · normal 0.19″

Frost dates for 91945

Frost-free in most years. No 32F freeze in at least 9 of 10 years at this station (NCEI reports no freeze dates; growing season = 365 days).

NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal freeze probabilities (32F) · CA SAN DIEGO MONTGOMERY FLD (USW00003131) 13.6 km away 20 yrs of record · about the same elevation

Newsletter · 91945

Frost alerts and planting reminders for 91945. Coming soon.

Ad strip · leaderboard 970×90 / 728×90

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

Fri 16
92° 72° gust 32 mph 💧5%
Clear
Sat 17
89° 65° gust 21 mph 💧5%
Clear
Sun 18
87° 65° gust 16 mph 💧0%
Clear
Mon 19
82° 63° gust 15 mph 💧8%
Clear
Tue 20
72° 59° gust 23 mph 💧68% · 0.06″
Rain
Wed 21
70° 57° gust 24 mph 💧68% · 0.45″
Rain
Thu 22
68° 57° gust 17 mph 💧32% · 0.11″
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 · 91945

Calendar: San Diego County, coastal (guide Regions 1-2). 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 91945

What USDA hardiness zone is 91945?

ZIP 91945 (Lemon Grove, CA) is in USDA zone 10b (35 to 40°F average annual extreme minimum), per the 2023 USDA Plant Hardiness Zone Map.

When is the last frost in 91945?

The nearest NOAA normals station (Ca San Diego Montgomery Fld, 13.6 km) records no 32°F freeze in at least 9 of 10 years (1991–2020).

Nearby ZIP codes

92114 San Diego 91977 Spring Valley 91941 La Mesa 92115 San Diego 91942 La Mesa 92105 San Diego

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 SAN DIEGO MONTGOMERY FLD (USW00003131) 13.6 km away 20 yrs of record · about the same elevation
  • 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: Iowa Environmental Mesonet ASOS archive (NWS/FAA METAR routine + special obs; one value per clock hour)
  • Raw data: /data/zip/91945.json