Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for Redlands, CA

Redlands, CA is in USDA zones 9b to 10a across its 3 ZIP codes. The median last spring frost is January 27 and the first fall frost December 19.

Redlands on the zone map

Outlined: its 2 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zones9b–10a25 to 35 °F
ZIP codes3
Last frostJan 27
First frostDec 19
Growing season329 days

9b 1 ZIP   10a 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Redlands, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 27median — 50% chance of a later frost
Safe for tender plantsFebruary 28only 10% chance of frost after
First fall frostDecember 19median — 10% chance by Dec 1
Growing season329 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 7 and returns around January 1.

From the NOAA station Redlands, CA, elevation 1,411 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in Redlands

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 16 – Dec 30
SpinachSow outdoors · Dec 16 – Jan 6
Broccoli, cabbageStart indoors · Nov 18 – Dec 2
Broccoli, cabbageTransplant · Jan 6 – Jan 20
Onion setsPlant outdoors · Dec 30 – Jan 13
PotatoesPlant outdoors · Jan 6 – Jan 20
LettuceSow outdoors · Dec 30 – Jan 13
Carrots, beetsSow outdoors · Jan 6 – Jan 20
TomatoesStart indoors · Dec 2 – Dec 16
TomatoesTransplant · Feb 3 – Feb 17
Peppers, eggplantStart indoors · Nov 18 – Dec 2
Peppers, eggplantTransplant · Feb 10 – Feb 24
BeansSow outdoors · Feb 3 – Feb 17
Sweet cornSow outdoors · Feb 3 – Feb 17
Cucumbers, squashSow outdoors · Feb 3 – Feb 17
Fall lettuce, spinachSow outdoors · Oct 24 – Nov 7
GarlicPlant cloves · Dec 5 – Jan 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 27) and first fall frost (Dec 19) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 92375 came on Jan 18 — 5 days earlier than the 1991–2020 average (Jan 23).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Redlands, CA

The soil mapped at the center of ZIP 92375 is Ramona — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH6.3slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Ramona sandy loam, 2 to 9 percent slopes, MLRA 19.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 92375; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Redlands, CA

Summer high96 °Faverage high, August
Winter low40 °Faverage low, December
Hot days104days a year at 90 °F or more
Freezing nights3nights a year at 32 °F or less
Growing degree days5,663base 50 °F — the season’s usable heat
Longest day14 h 25 mindaylight on June 21
Shortest day9 h 53 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation12.9 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 67 °F, low 41 °F 67°41° JanFebruary: average high 67 °F, low 42 °F 67°42° FebMarch: average high 71 °F, low 45 °F 71°45° MarApril: average high 76 °F, low 48 °F 76°48° AprMay: average high 80 °F, low 52 °F 80°52° MayJune: average high 89 °F, low 56 °F 89°56° JunJuly: average high 95 °F, low 63 °F 95°63° JulAugust: average high 96 °F, low 63 °F 96°63° AugSeptember: average high 92 °F, low 60 °F 92°60° SepOctober: average high 83 °F, low 53 °F 83°53° OctNovember: average high 75 °F, low 45 °F 75°45° NovDecember: average high 67 °F, low 40 °F 67°40° Dec

Precipitation by month inches

0″1″2″3″January: 2.76 in precipitation 2.8 JanFebruary: 2.99 in precipitation 3.0 FebMarch: 2.01 in precipitation 2.0 MarApril: 0.91 in precipitation 0.9 AprMay: 0.35 in precipitation 0.3 MayJune: 0.10 in precipitation 0.1 JunJuly: 0.10 in precipitation 0.1 JulAugust: 0.09 in precipitation 0.1 AugSeptember: 0.13 in precipitation 0.1 SepOctober: 0.53 in precipitation 0.5 OctNovember: 0.89 in precipitation 0.9 NovDecember: 2.01 in precipitation 2.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Redlands, CA (within 1 mile); precipitation: Redlands, CA (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Redlands

923739b
25 to 30 °F
9237410a
30 to 35 °F
9237510a
30 to 35 °F

California planting zones →

Questions about Redlands

What planting zone is Redlands, CA?

Redlands, CA is in USDA hardiness zones 9b to 10a on the 2023 map (9b: 25 to 30 °F; 10a: 30 to 35 °F).

When is the last frost in Redlands, CA?

The median last spring frost is January 27 and the median first fall frost is December 19 (NOAA 1991–2020 normals, Redlands station).

When can I plant a garden in Redlands, CA?

Cool-season crops like peas and spinach go in around Dec 16 – Jan 6; tomatoes, peppers, beans and squash after about Feb 3, once frost risk has passed.

What kind of onions grow in Redlands, CA?

Intermediate onions: the longest day is 14 h 25 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Redlands, CA get?

About 12.9 inches of precipitation a year (NOAA 1991–2020 normals).