Garden Climate for San Diego & Bonita: 91902, 92104, 92105, 92108, 92114, 92115, 92116, 92120, 92123, 92124, 92139, 92182

Zone 10b · Frost-free in most years · Soil 70.0°F today (modeled) · See your place on the 2023 USDA zone map

ZIPs in this area

What differs between these ZIPs: elevation, chill hours, soil temperature. Everything else on this page is the same for all of them. The page below shows 92123 (closest to the area's middle elevation).

ZIP	Town	Elevation	Zone	Last frost	First frost	Chill hrs last season	Soil now
91902	Bonita	94 ft	10b	frost-free	frost-free	56	71.4°F
92104	San Diego	350 ft	10b	frost-free	frost-free	31	71.7°F
92105	San Diego	297 ft	10b	frost-free	frost-free	31	71.8°F
92108	San Diego	75 ft	10b	frost-free	frost-free	41	71.1°F
92114	San Diego	407 ft	10b	frost-free	frost-free	56	71.5°F
92115	San Diego	470 ft	10b	frost-free	frost-free	41	71.3°F
92116	San Diego	394 ft	10b	frost-free	frost-free	41	71.5°F
92120	San Diego	358 ft	10b	frost-free	frost-free	41	71.8°F
92123	San Diego	391 ft	10b	frost-free	frost-free	41	70.0°F
92124	San Diego	410 ft	10b	frost-free	frost-free	41	69.2°F
92139	San Diego	305 ft	10b	frost-free	frost-free	56	71.8°F
92182	San Diego	442 ft	10b	frost-free	frost-free	41	71.5°F

Why grouped: these are urban and suburban lowland ZIPs (under about 1,500 ft and within 40 km of the ocean) whose numbers are close: all frost-free in most years, last season's chill hours all in the <100 range, the same inland setting and the same 820 ft elevation band. Each ZIP still uses its own nearest suitable stations; see the table for exact values.

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

USDA Plant Hardiness Zone Map · San Diego focus

Zone

10b

USDA 2023 · 35 to 40°F

Last frost

None

frost-free ≥9 of 10 yrs

Soil temp Modeled

70.0°F

↓ 6.8° in 7 days

Chill hours

—

starts Nov 1

Rain

1.02″

since Oct 1 · normal 0.19″

Frost dates for 92123

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) 2.1 km away 20 yrs of record · about the same elevation

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

Fri 16

95° 72° gust 24 mph 💧2%

Clear

Sat 17

91° 66° gust 16 mph 💧2%

Clear

Sun 18

87° 66° gust 20 mph 💧1%

Clear

Mon 19

82° 63° gust 17 mph 💧9%

Clear

Tue 20

72° 60° gust 23 mph 💧68% · 0.04″

Rain

Wed 21

71° 58° gust 23 mph 💧68% · 0.50″

Rain

Thu 22

69° 58° gust 16 mph 💧33% · 0.12″

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 · 92123

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 cloth Soil thermometer

Harvest planner

Create an interactive chart of your garden plan to see estimated harvest times, harvest size, and get recommendations based on your unique growing plan!

Open planner for 92123 →

Soil temperature Modeled

Daily average 70.0°F on 2026-10-15, mean of 6 cm and 18 cm model layers (~4-5 in). Modeled

7-day trend: 76.7 → 75.0 → 71.4 → 69.3 → 67.6 → 67.2 → 70.0

Source: Open-Meteo forecast API soil model (non-commercial terms).

Why modeled: no operational USCRN within 60 km and 300 m elevation

Chill hours this season

This season

—

Counting starts Nov 1

Last year by today

—

Counting starts Nov 1

10-year average by today

—

Counting starts Nov 1

Last season's total

Nov 1–Apr 30 · 2025-26 · 100% of hours recorded

All values are hours between 32°F and 45°F. Observed at SAN DIEGO/MONTG (MYF) 2.0 km away · about the same elevation · Iowa Environmental Mesonet ASOS archive (NWS/FAA METAR routine + special obs; one value per clock hour). Chill hours = observed hours with 32F <= T <= 45F, counted from Nov 1. Missing hours are not filled. Past seasons use the same station and method; the average only includes seasons with >=80% hourly coverage.

Rainfall this season

This water year (since Oct 1)

1.02″

Oct 1–Oct 15 · 100% of days recorded · Oct 1–Oct 13 San Diego Montgomery Field (GHCN) + Oct 14–Oct 15 Montg (airport ASOS)

Last year by Oct 15

0.50″

Oct 1–Oct 15, 2025 · 100% of days recorded

30-yr normal by Oct 15

0.19″

Oct 1–Oct 15 · NOAA 1991–2020 normal · full water year 11.02″

Last water year total

8.94″

Oct 1 2025–Sep 30 2026 · 100% of days recorded

Rain and melted snow, inches. Observed at CA SAN DIEGO MONTGOMERY FLD (USW00003131) 2.1 km away · about the same elevation · NOAA NCEI GHCN-Daily (values with a quality flag are skipped; daily reports usually lag a few days to weeks, latest Oct 13). Normal: NOAA NCEI U.S. Climate Normals 1991–2020 (daily). Season starts Oct 1 (water year (Oct 1–Sep 30)). Days after Oct 13 come from SAN DIEGO/MONTG (MYF) 2.0 km away · about the same elevation: Iowa Environmental Mesonet ASOS daily summary (METAR precipitation; a reporting day with no precip group counts as 0.00). That station uses the same distance, elevation and coastal rules; only this water year is filled. Comparisons run through the last complete day.

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Zone border tip

The 2023 USDA map puts 92123's point in zone 10b. The nearest different zone (11a) is about 4.7 km away on the map. That's close, so if you garden on that side, base plant choices on your exact spot, not the ZIP average.

Recent from the blog

Posts are coming soon. Planned: "Are frost dates shifting? 1991–2020 vs 1981–2010", "Reading chill hours for fruit trees".

Blog →

Questions about 92123

What USDA hardiness zone is 92123?

ZIP 92123 (San Diego, 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 92123?

The nearest NOAA normals station (Ca San Diego Montgomery Fld, 2.1 km) records no 32°F freeze in at least 9 of 10 years (1991–2020).

Nearby ZIP codes

92111 San Diego 92108 San Diego 92124 San Diego 92116 San Diego 92120 San Diego 92117 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) 2.1 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/92123.json

Garden Climate for San Diego & Bonita: 91902, 92104, 92105, 92108, 92114, 92115, 92116, 92120, 92123, 92124, 92139, 92182

ZIPs in this area

USDA Plant Hardiness Zone Map · San Diego focus

Frost dates for 92123

Newsletter · 92123

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

What to grow when · 92123

Questions about 92123

Nearby ZIP codes

Sources for this page