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

Planting zone for Paso Robles, CA

Paso Robles, CA is in USDA zone 9a across its 2 ZIP codes. The median last spring frost is March 15 and the first fall frost November 10.

Paso Robles on the zone map

Outlined: its 1 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.

Zone9a20 to 25 °F
ZIP codes2
Last frostMar 15
First frostNov 10
Growing season238 days

9a 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 Paso Robles, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 15median — 50% chance of a later frost
Safe for tender plantsApril 13only 10% chance of frost after
First fall frostNovember 10median — 10% chance by Oct 23
Growing season238 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 9 and returns around November 26.

From the NOAA station Paso Robles, CA, elevation 732 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 Paso Robles

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 1 – Feb 15
SpinachSow outdoors · Feb 1 – Feb 22
Broccoli, cabbageStart indoors · Jan 4 – Jan 18
Broccoli, cabbageTransplant · Feb 22 – Mar 8
Onion setsPlant outdoors · Feb 15 – Mar 1
PotatoesPlant outdoors · Feb 22 – Mar 8
LettuceSow outdoors · Feb 15 – Mar 1
Carrots, beetsSow outdoors · Feb 22 – Mar 8
TomatoesStart indoors · Jan 18 – Feb 1
TomatoesTransplant · Mar 22 – Apr 5
Peppers, eggplantStart indoors · Jan 4 – Jan 18
Peppers, eggplantTransplant · Mar 29 – Apr 12
BeansSow outdoors · Mar 22 – Apr 5
Sweet cornSow outdoors · Mar 22 – Apr 5
Cucumbers, squashSow outdoors · Mar 22 – Apr 5
Fall lettuce, spinachSow outdoors · Sep 15 – Sep 29
GarlicPlant cloves · Oct 27 – Dec 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 15) and first fall frost (Nov 10) 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 93447 came on Jan 30 — about the same time as the 1991–2020 average (Jan 30).

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 Paso Robles, CA

The soil mapped at the center of ZIP 93447 is Hanford — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH6.7neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Hanford and Greenfield soils, 0 to 2 percent slopes.

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 93447; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Paso Robles, CA

Summer high94 °Faverage high, August
Winter low33 °Faverage low, December
Hot days92days a year at 90 °F or more
Freezing nights45nights a year at 32 °F or less
Growing degree days4,015base 50 °F — the season’s usable heat
Longest day14 h 35 mindaylight on June 21
Shortest day9 h 44 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation12.2 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 61 °F, low 35 °F 61°35° JanFebruary: average high 63 °F, low 37 °F 63°37° FebMarch: average high 68 °F, low 40 °F 68°40° MarApril: average high 74 °F, low 41 °F 74°41° AprMay: average high 81 °F, low 46 °F 81°46° MayJune: average high 89 °F, low 50 °F 89°50° JunJuly: average high 93 °F, low 54 °F 93°54° JulAugust: average high 94 °F, low 53 °F 94°53° AugSeptember: average high 90 °F, low 50 °F 90°50° SepOctober: average high 81 °F, low 44 °F 81°44° OctNovember: average high 69 °F, low 37 °F 69°37° NovDecember: average high 60 °F, low 33 °F 60°33° Dec

Precipitation by month inches

0″1″2″3″January: 2.74 in precipitation 2.7 JanFebruary: 2.48 in precipitation 2.5 FebMarch: 2.42 in precipitation 2.4 MarApril: 0.60 in precipitation 0.6 AprMay: 0.31 in precipitation 0.3 MayJune: 0.04 in precipitation 0.0 JunJuly: 0.08 in precipitation 0.1 JulAugust: 0.01 in precipitation 0.0 AugSeptember: 0.06 in precipitation 0.1 SepOctober: 0.56 in precipitation 0.6 OctNovember: 0.87 in precipitation 0.9 NovDecember: 1.98 in precipitation 2.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Paso Robles Municipal Airport, CA (7 mi away); precipitation: Paso Robles Municipal Airport, CA (7 mi away). Daylight is calculated from latitude.

ZIP codes in Paso Robles

934469a
20 to 25 °F
934479a
20 to 25 °F

California planting zones →

Questions about Paso Robles

What planting zone is Paso Robles, CA?

Paso Robles, CA is in USDA hardiness zone 9a on the 2023 map (9a: 20 to 25 °F).

When is the last frost in Paso Robles, CA?

The median last spring frost is March 15 and the median first fall frost is November 10 (NOAA 1991–2020 normals, Paso Robles station).

When can I plant a garden in Paso Robles, CA?

Cool-season crops like peas and spinach go in around Feb 1 – Feb 22; tomatoes, peppers, beans and squash after about Mar 22, once frost risk has passed.

What kind of onions grow in Paso Robles, CA?

Intermediate onions: the longest day is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Paso Robles, CA get?

About 12.2 inches of precipitation a year (NOAA 1991–2020 normals).