USDA zone 8b in California
USDA plant hardiness zone 8b covers 49 locations across California (average annual extreme minimum 15 to 20 °F): Aguanga, CA, Alta, CA, Anza, CA, Anza, CA, Apple Valley, CA, Arnold, CA, and 43 more. Average last spring frost across this group ranges February 4 (Nipomo) to May 29 (Big Bend), and growing seasons run 113–301 days (Big Bend to Nipomo) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every California location's own frost dates; the printable planting calendar uses Keene, this group's median-season location.
- USDA zone
- 8b15 to 20 °F
- Last frost range
- Feb 4–May 29avg, 32°F
- First frost range
- Sep 19–Dec 4avg, 32°F
- Growing season range
- 113–301days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Aguanga | — | Henshaw Dam | Apr 18 | Oct 26 | 189 |
| Alta | Washington | Blue Canyon Ap | May 4 | Nov 4 | 183 |
| Anza | — | Palomar Mtn Obsy | Apr 29 | Nov 18 | 201 |
| Anza | — | Idyllwild Fire Dept | May 16 | Oct 24 | 160 |
| Apple Valley | Victorville, Hesperia, Phelan, Adelanto, Oak Hills, Silver Lakes, +1 more | Victorville | Mar 18 | Nov 11 | 233 |
| Arnold | Wilseyville, Hathaway Pines | Calaveras Big Trees | May 7 | Oct 28 | 169 |
| Bass Lake | El Portal | So Entrance Yosemite Np | May 24 | Oct 10 | 137 |
| Big Bend | — | Hat Creek | May 29 | Sep 19 | 113 |
| Bodfish | Wofford Heights, Glennville, Sugarloaf Saw Mill | Glennville | May 11 | Oct 17 | 155 |
| California | Mojave, North Edwards | Mojave | Mar 15 | Nov 17 | 241 |
| California | Boron | Randsburg | Mar 19 | Nov 25 | 251 |
| Castella | — | Dunsmuir Trtmt Pl | Apr 23 | Oct 27 | 185 |
| Cedar Ridge | Soulsbyville, Mi-Wuk, Tuolumne | Sonora | Apr 9 | Nov 9 | 213 |
| Creston | — | Paso Robles | Mar 15 | Nov 10 | 238 |
| Descanso | Pine Valley | Cuyamaca | Apr 19 | Oct 27 | 190 |
| Douglas | Lewiston | Trinity Rvr Hatchery | Apr 23 | Oct 22 | 178 |
| Etna | — | Cecilville | Apr 27 | Oct 21 | 176 |
| Frazier Park | Meiners Oaks | Ojai | Mar 21 | Nov 15 | 235 |
| Golden Hills | — | Tehachapi 4 Se | Apr 28 | Oct 26 | 183 |
| Goodyears Bar | Alleghany | Downieville | Apr 28 | Oct 25 | 178 |
| Greeley Hill | — | Cherry Valley Dam | May 2 | Nov 4 | 183 |
| Happy Camp | Wautec | Orleans | Mar 12 | Nov 26 | 262 |
| Happy Camp | — | Ruch | May 4 | Oct 13 | 160 |
| Hayfork | Ruth, Hyampom, Trinity | Big Bar 4 E | Apr 16 | Oct 31 | 197 |
| Junction | Weaverville | Weaverville | May 3 | Oct 11 | 159 |
| Keeler | — | Independence | Mar 31 | Nov 9 | 224 |
| Keene * | — | Loraine 5 Nne | Apr 22 | Nov 13 | 201 |
| Kelseyville | — | Cloverdale | Feb 25 | Dec 3 | 279 |
| Lake Arrowhead | Crestline | Lake Arrowhead | May 5 | Nov 2 | 176 |
| Lake Hughes | — | Fairmont | Apr 6 | Nov 29 | 236 |
| Lake Los Angeles | — | Palmdale Ap | Mar 18 | Nov 15 | 241 |
| Lakeport | — | Ukiah Muni Ap | Mar 5 | Nov 21 | 259 |
| Lebec | — | Sandberg | Apr 15 | Nov 26 | 224 |
| Lucerne Valley | — | Big Bear Lake | May 27 | Oct 4 | 131 |
| Magalia | Stirling | De Sabla | Apr 17 | Nov 11 | 206 |
| Nice | Upper Lake | Potter Valley Powerhouse | Apr 8 | Nov 6 | 211 |
| Nipomo | — | Twitchell Dam | Feb 4 | Dec 4 | 301 |
| Olancha | Kennedy Meadows, Darwin | Haiwee | Apr 17 | Nov 1 | 196 |
| Palmdale | — | Palmdale | Mar 10 | Nov 19 | 248 |
| Piñon Hills | — | Wrightwood | May 16 | Oct 13 | 151 |
| Piñon Hills | Lake Los Angeles, Littlerock | Pearblossom | Mar 13 | Dec 1 | 258 |
| Pierpoint | — | Lindsay | Feb 20 | Nov 30 | 284 |
| Pine Mountain Club | — | New Cuyama Fire Stn | Apr 15 | Nov 4 | 201 |
| Pollock Pines | Grizzly Flats | Pacific House | Apr 26 | Nov 2 | 191 |
| Ridgecrest Heights | — | China Lake Naf | Mar 11 | Nov 12 | 244 |
| Rosamond | — | Lancaster Wm J Fox Fld | Apr 3 | Nov 1 | 211 |
| Ruth | — | Covelo | Apr 23 | Oct 19 | 179 |
| San Miguel | — | Coalinga | Feb 14 | Nov 30 | 292 |
| Shandon | — | Paso Robles Muni Ap | Apr 4 | Nov 5 | 213 |
* Keene is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Keene, representative)
Computed from Keene's average frost dates — the median-season location in this Californiazone 8b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Feb 25 – Mar 11 | Apr 29 – May 6 | Jun 28 – Jul 18 | — | matures comfortably |
| Pepper | Very tender | Feb 11 – Feb 25 | May 6 – May 13 | Jul 5 – Aug 4 | — | matures comfortably |
| Cucumber | Tender | Mar 25 – Apr 1 | Apr 29 – May 6 | Jun 18 – Jul 8 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 29 – May 6 | Jun 13 – Jun 28 | — | matures comfortably |
| Bush bean | Tender | — | Apr 29 – May 6 | Jun 18 – Jun 28 | Sep 14 – Sep 24 | matures comfortably |
| Sweet corn | Tender | — | Apr 22 – May 6 | Jun 21 – Jul 21 | — | matures comfortably |
| Basil | Very tender | Mar 11 – Mar 25 | Apr 29 – May 6 | May 29 – Jun 13 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 11 – Mar 25 | Mar 25 – Apr 8 | May 9 – May 24 | Aug 31 – Sep 15 | matures comfortably |
| Pea | Hardy | — | Mar 11 – Mar 25 | May 5 – May 20 | Aug 21 – Sep 5 | matures comfortably |
| Spinach | Hardy | — | Mar 11 – Mar 25 | Apr 20 – Apr 30 | Sep 10 – Sep 20 | matures comfortably |
| Carrot | Half-hardy | — | Apr 1 – Apr 8 | May 31 – Jun 20 | Aug 11 – Aug 31 | matures comfortably |
| Broccoli | Half-hardy | Feb 25 – Mar 11 | Mar 25 – Apr 8 | May 19 – Jun 8 | Aug 16 – Sep 5 | matures comfortably |
Which crops fit this growing season
Using Keene's own 201-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Keene)
From NOAA's 1991–2020 Climate Normals at station USC00045100. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 12 | Jun 4 | Oct 28 | Nov 13 | 165 |
| 32°F (freeze) | Apr 22 | May 14 | Nov 13 | Dec 1 | 201 |
| 28°F | Mar 28 | Apr 21 | Dec 1 | Dec 18 | 247 |
| 24°F | Feb 17 | Apr 2 | Dec 15 | Jan 17 | 303 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 49 locations is 3,560; Keene's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 3,276 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 6,078 | cool-season crops (brassicas, greens) |
Hardiness zone 8b in California
Zone 8b means an average annual extreme minimum winter temperature of about 15 to 20 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. California spans 12 hardiness zones in this dataset — see all California locations for the full range, including zones5b, 6a, 6b, 7a, 7b, 8a, 9a, 9b, 10a, 10b, 11a.
Explore zone 8b in other states at zone 8b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 8b mean in California?
- Zone 8b means an average annual extreme minimum winter temperature of 15 to 20 °F — the standard USDA measure of which perennials survive winter. 49 locations in California fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in California's zone 8b is the growing season longest?
- Nipomo runs the longest season on this page at about 301 days; Big Bend is shortest at about 113 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in California's zone 8b?
- Using Keene's frost dates (this page's median-season location): start seeds indoors about Feb 25 – Mar 11, then transplant outside about Apr 29 – May 6. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in California's zone 8b have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 49 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.