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

Planting zone for 93447 — Paso Robles, CA

ZIP code 93447 (Paso Robles, San Luis Obispo County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is April 4 and the first fall frost November 5.

Where ZIP 93447 is

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
Coldest night−6.7 to −3.9 °C
Last frostApr 4
First frostNov 5
2012 zone9a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Paso Robles, CA…

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 frostApril 4median — 50% chance of a later frost
Safe for tender plantsApril 27only 10% chance of frost after
First fall frostNovember 5median — 10% chance by Oct 17
Growing season213 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 22 and returns around November 21.

From the NOAA station Paso Robles Municipal Airport, CA — 7 miles away, elevation 810 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 93447

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 21 – Mar 7
SpinachSow outdoors · Feb 21 – Mar 14
Broccoli, cabbageStart indoors · Jan 24 – Feb 7
Broccoli, cabbageTransplant · Mar 14 – Mar 28
Onion setsPlant outdoors · Mar 7 – Mar 21
PotatoesPlant outdoors · Mar 14 – Mar 28
LettuceSow outdoors · Mar 7 – Mar 21
Carrots, beetsSow outdoors · Mar 14 – Mar 28
TomatoesStart indoors · Feb 7 – Feb 21
TomatoesTransplant · Apr 11 – Apr 25
Peppers, eggplantStart indoors · Jan 24 – Feb 7
Peppers, eggplantTransplant · Apr 18 – May 2
BeansSow outdoors · Apr 11 – Apr 25
Sweet cornSow outdoors · Apr 11 – Apr 25
Cucumbers, squashSow outdoors · Apr 11 – Apr 25
Fall lettuce, spinachSow outdoors · Sep 10 – Sep 24
GarlicPlant cloves · Oct 22 – Nov 26
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 4) and first fall frost (Nov 5) 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.

Nearby ZIP codes

3 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

934469a
Paso Robles, CA · 7 mi
934518b
San Miguel, CA · 14 mi
934659a
Templeton, CA · 15 mi
934269a
Bradley, CA · 17 mi
934229a
Atascadero, CA · 20 mi
934328b
Creston, CA · 23 mi
9342810a
Cambria, CA · 23 mi
934239a
Atascadero, CA · 23 mi

All 2 ZIP codes in Paso Robles → · California planting zones →

Questions about 93447

What planting zone is ZIP code 93447?

ZIP code 93447 (Paso Robles, CA) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in Paso Robles, CA?

The median last spring frost (32 °F) near 93447 is April 4; after April 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Paso Robles Municipal Airport station.

When is the first frost in Paso Robles, CA?

The median first fall frost near 93447 is November 5, giving a median frost-free growing season of 213 days.

When should I plant tomatoes in 93447?

Start tomato seeds indoors around Feb 7 – Feb 21 and set transplants outside around Apr 11 – Apr 25, one to three weeks after the median last frost.

How much rain and snow does 93447 get?

About 12.2 inches of precipitation a year (NOAA 1991–2020 normals, Paso Robles Municipal Airport station).

How hot do summers get in Paso Robles, CA?

The average high peaks at 94 °F in August, with about 92 days a year at 90 °F or more.

What kind of soil does 93447 have?

The USDA soil survey maps Hanford at the center of ZIP 93447: fine sandy loam, well drained, pH about 6.7 (neutral).

Did spring come early in Paso Robles, CA in 2026?

Spring leaf-out near 93447 came on Jan 30 in 2026, about the same as the 1991–2020 average (Jan 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Paso Robles, CA?

Intermediate onions: the longest day near 93447 is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.