Place guide
Planting zones in San Luis Obispo-Paso Robles, CA
This metro spans USDA zones 8b to 10a, so there is no single zone for San Luis Obispo-Paso Robles, CA and anyone who gives you one is rounding. 39% of its ZIP codes are zone 10a; the rest are not.
Your ZIP code
Get the exact answer for your address
Everything above describes San Luis Obispo-Paso Robles, CA as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.
San Luis Obispo-Paso Robles, CA does not have one planting answer
Its own weather stations disagree about 32 of the 32 crops in this table right now, so any single list would be wrong for part of the metro area. That is not a gap in the data — it is what the data says.
- Shortest season
- 213 days
PASO ROBLES MUNI AP, CA US (USW00093209) - Longest season
- 365 days
MORRO BAY FIRE DEPT, CA US (USC00045866)
152 days of growing season separate those two stations, and both serve ZIP codes in San Luis Obispo-Paso Robles, CA. The ZIP lookup above answers for one address instead of averaging a place that has no average.
Why the hardiness zone does not settle this
A USDA zone is a winter-minimum statistic. It was never a growing-season one, and it does not behave like one: within a single zone the growing season runs a median 54 days wider at the 10th–90th percentile, and annual growing degree days vary by 2.02×.
The zones also overlap rather than stack — 30% of zone 6b freezes before the median zone 6a station. The zone tells you what survives your winter; the station tells you what finishes before your autumn.
The growing season at one or more of this metro area's stations crosses 1 January, so a one-year bar would have to start the season after it ended. No chart is drawn rather than a misleading one.
Which zone you are in depends where you are
San Luis Obispo-Paso Robles, CA covers 4 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 39% in zone 10a and wrong for the other 61%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 10a | 9 | 39% | |
| 9b | 8 | 35% | |
| 8b | 3 | 13% | |
| 9a | 3 | 13% |
Zones are published per ZIP code, so yours is exact even though the metro's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
No freeze range is shown for San Luis Obispo-Paso Robles, CA, because the freeze window here crosses New Year, so an earliest-to-latest range would be arithmetic on dates that do not sit in order. The tools below still answer for individual ZIP codes here, and will say what applies.
Your growing season
NOAA publishes a growing-season length for each station, and across the 9 stations serving San Luis Obispo-Paso Robles, CA it runs 213–365 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 68–92 °F , at or above the 90 °F point where cool-season crops bolt and tomato and pepper pollen fails — so midsummer sowings of lettuce and its relatives are worth holding here. Summer rain over the same months runs 0.1–0.3" across those 9 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. The middle station covers about 1% of it, so a summer garden here is watered rather than rained on. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 76 °F summer afternoon drying the soil faster than a cool one.
What survives the winter changes across San Luis Obispo-Paso Robles, CA
Of 74 perennial fruits, nuts, berries, vegetables and herbs, 54 come through the winter in zone 8b and only 25 in zone 10a. That is a different garden at each end of the same metro.
| Zone | ZIPs | Survive | Fail for being too warm |
|---|---|---|---|
| 8b | 3 | 54 of 74 | 11 |
| 9a | 3 | 46 of 74 | 25 |
| 9b | 8 | 40 of 74 | 32 |
| 10a | 9 | 25 of 74 | 49 |
The last column is the counterintuitive one, and it is why the totals do not simply rise as the winters get milder. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the summer heat that comes with it. See the full list with reasons.
At least one station here freezes across the new year, which puts the two ends of a spread on opposite sides of the calendar. Drawing it would produce a bar spanning almost the whole year and meaning nothing, so none is drawn.
The 9 stations behind these numbers
All 9 NOAA stations whose normals this page quotes, spanning about 87 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole metro area.
A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.
Every figure above comes from these, and each is named so you can check it. Which station serves a given ZIP code, and how far away it is, varies across the metro — the table below gives it per ZIP code rather than this page averaging it.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Hearst Castle, CA | USC00043882 | February 13 | February 1 | 365 days |
| Morro Bay Fire Dept, CA | USC00045866 | January 19 | January 14 | 365 days |
| Paso Robles Muni AP, CA | USW00093209 | April 4 | November 5 | 213 days |
| Paso Robles, CA | USC00046730 | March 15 | November 10 | 238 days |
| Pismo Beach, CA | USC00046943 | February 1 | January 4 | 362 days |
| San Luis Obispo AP, CA | USW00093206 | January 31 | December 11 | 319 days |
| San Luis Obispo Poly, CA | USC00047851 | January 16 | December 25 | 349 days |
| Santa Maria Public AP, CA | USW00023273 | February 4 | December 13 | 315 days |
| Twitchell Dam, CA | USC00049111 | February 4 | December 4 | 301 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Every ZIP code in San Luis Obispo-Paso Robles, CA
Zones are published per ZIP code, not per metro area, so this is the exact answer rather than the metro area's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.
| ZIP code | USDA zone | Nearest NOAA station | Distance |
|---|---|---|---|
| 93401 | 9b | San Luis Obispo AP, CA | 2.3 km |
| 93402 | 10a | Morro Bay Fire Dept, CA | 8.0 km |
| 93405 | 9b | San Luis Obispo Poly, CA | 6.6 km |
| 93407 | 9b | San Luis Obispo Poly, CA | 0.7 km |
| 93408 | 10a | San Luis Obispo Poly, CA | 5.5 km |
| 93409 | 9b | San Luis Obispo Poly, CA | 3.8 km |
| 93410 | 9b | San Luis Obispo Poly, CA | 0.5 km |
| 93420 | 9b | San Luis Obispo AP, CA | 16.4 km |
| 93422 | 9a | Morro Bay Fire Dept, CA | 17.8 km |
| 93424 | 10a | Pismo Beach, CA | 10.3 km |
| 93428 | 10a | Hearst Castle, CA | 15.9 km |
| 93430 | 10a | Morro Bay Fire Dept, CA | 15.9 km |
| 93432 | 8b | Paso Robles, CA | 24.8 km |
| 93433 | 10a | Pismo Beach, CA | 7.2 km |
| 93442 | 9b | Morro Bay Fire Dept, CA | 5.6 km |
| 93444 | 9b | Santa Maria Public AP, CA | 16.0 km |
| 93445 | 10a | Pismo Beach, CA | 14.1 km |
| 93446 | 9a | Paso Robles, CA | 4.5 km |
| 93449 | 10a | Pismo Beach, CA | 2.7 km |
| 93452 | 10a | Hearst Castle, CA | 8.5 km |
| 93453 | 8b | Twitchell Dam, CA | 29.6 km |
| 93461 | 8b | Paso Robles Muni AP, CA | 32.8 km |
| 93465 | 9a | Paso Robles, CA | 10.4 km |
ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.
Your own ZIP
Work out your own dates
Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.
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What survives my winter?
Runs on the hardiness zone, so it answers for all of San Luis Obispo-Paso Robles, CA at once — zone across 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Other places to compare
Gardening in California — zones 5b– 11a covers the whole state: how its 1,788 ZIP codes divide between 12 hardiness zones, and the freeze dates across every NOAA station in it.
Other metro areas in CA:
- Yuba City, CA Zones 9a–9b
- Chico, CA Zones 8b–9b
- Merced, CA Zones 9a–9b
- Santa Cruz-Watsonville, CA Zones 9a–10a
- El Centro, CA Zones 9b–10a
- Vallejo, CA Zone 9b
- Napa, CA Zones 9a–9b
- Hanford-Corcoran, CA Zones 9a–9b
- Los Angeles-Long Beach-Anaheim, CA Zones 7b–11a
- San Francisco-Oakland-Fremont, CA Zones 9b–10b
- Riverside-San Bernardino-Ontario, CA Zones 7a–10b
- Sacramento-Roseville-Folsom, CA Zones 6b–9b
Gear
If you want to act on this
Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.
- Soaker hose and drip kitsThe stations here publish no ordinary freeze window, so frost is not what limits the season — water is, through a summer that does not stop.
As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.
Sources
Where these numbers come from
The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.
This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.