Fall in zone 9bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 93410 (California Polytechnic State University, CA)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, San Luis Obispo Poly, CA (0 miles away).
Freezes are uncommon here
NOAA's normals for this station show a 32°F night in about 68% of years (about 3 freezing night(s) a year on average). The dates below describe freeze timing for the station's record; in many years there may be no 32°F freeze at all.
- Average last spring frostJan 1650% chance of a 32°F freeze after this date
- Average first fall frostDec 2550% chance of a 32°F freeze by this date
- Growing season (frost-free)349 daysmedian, 32°F threshold
- USDA hardiness zone9b25 to 30°F avg. coldest night
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This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Freezes are uncommon here, so frost-based timing is rough. Local extension calendars for frost-free areas use months.
Soil temperature now
2-inch depth
78°F 55°F or warmer
24-hour average · latest 72°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Cochora Ranch (61 mi).
4-inch depth
77°F 55°F or warmer
24-hour average · latest 78°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Cochora Ranch (61 mi).
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
The latest National Weather Service 7-day forecast and any Frost Advisory or Freeze Warning for 93410 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 77°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): not yet. Apply as soil cools toward 70°F (typically September to October).
Fertilizer window
Lawn region: California coastal and valleys. Timing only; always follow the product label.
- Bermudagrass (warm-season): Spring: Several weeks after the lawn is fully green (April–May) (about Mar 3 here, using green-up about 3–4 weeks after your average last frost); Summer: Every 4–6 weeks through mid-August (heaviest feeder of the group); Late: Light, low-nitrogen/high-potassium feeding about 4 weeks before first frost, or skip. Avoid: Heavy late-fall nitrogen (linked to spring dead spot).
- Tall fescue (cool-season): Early fall: September (main feeding); Late fall: November, while still green; Late winter: Optional light feeding February–March. Avoid: Feeding after mid-spring and through summer in the transition zone (stress and brown patch).
Plant now
- Lettuce: fall sowing Oct 16–Nov 13
- Kale: fall transplant Oct 2–30
- Collards: fall transplant Oct 2–30
- Kohlrabi: fall sowing Oct 16–30
- Swiss chard: fall sowing Oct 16–30
- Beet: fall sowing Oct 16–30
- Turnip: fall sowing Oct 16–30
- Green onion / scallion: fall sowing Oct 16–30
- Strawberry (plants): fall transplant Oct 16–Nov 13
Coming up in the next 3 weeks
- Pepper (sweet and hot): start seeds indoors Nov 7–21
- Eggplant: start seeds indoors Nov 7–21
- Lettuce: fall transplant Oct 30–Nov 20
- Spinach: fall sowing Oct 30–Nov 20
- Broccoli: start seeds indoors Nov 7–21
- Cabbage: start seeds indoors Nov 7–21
- Cauliflower: start seeds indoors Nov 7–21
- Brussels sprouts: start seeds indoors Oct 24–Nov 7
- Bok choy / Asian greens: fall sowing Oct 30–Nov 13
- Arugula: fall sowing Oct 30–Nov 27
- Mustard greens: fall sowing Oct 30–Nov 13
- Onion (bulbing): start seeds indoors Oct 24–Nov 7
Prune now
No frost-timed pruning windows are open this week.
Spring-flowering shrubs are pruned right after their flowers fade, not by date. See the pruning guide.
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Dec 11 (prior Dec) |
| 50% (the "average" last frost) | Jan 16 |
| 10% (cautious: only 1 year in 10 freezes later) | Feb 26 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Nov 25 |
| 50% (the "average" first frost) | Dec 25 |
| 90% (late: most years have frozen by now) | Feb 12 (next year) |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Feb 28 | Dec 1 |
| 32°F (freeze) | Jan 16 | Dec 25 |
| 28°F (hard freeze) | Jan 9 | Jan 6 (next year) |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
Vegetable planting calendar for 93410
Dates count from your average last spring frost (Jan 16) and first fall frost (Dec 25). Half of years have a frost after the spring date, so give tender crops (tomatoes, peppers, squash) some slack.
| Crop | Start indoors | Spring planting | Fall planting |
|---|---|---|---|
| Tomato | Nov 21–Dec 5 | Jan 23–Feb 6 (transplant) | Aug 28–Sep 25 (transplant) |
| Pepper (sweet and hot) | Nov 7–21 | Jan 30–Feb 13 (transplant) | Sep 4–25 (transplant) |
| Eggplant | Nov 7–21 | Jan 30–Feb 13 (transplant) | Sep 4–25 (transplant) |
| Tomatillo | Nov 21–Dec 5 | Jan 23–Feb 6 (transplant) | – |
| Lettuce | Nov 21–Dec 5 | Dec 26–Jan 16 (transplant) Dec 19–Jan 30 (sow outdoors) | Oct 30–Nov 20 (transplant) Oct 16–Nov 13 (sowing) |
| Spinach | – | Dec 5–26 (sow outdoors) | Oct 30–Nov 20 (sowing) |
| Kale | Nov 21–Dec 5 | Dec 19–Jan 2 (transplant) Dec 19–Jan 2 (sow outdoors) | Oct 2–30 (transplant) Sep 18–Oct 16 (sowing) |
| Collards | Nov 21–Dec 5 | Dec 19–Jan 16 (transplant) Dec 19–Jan 16 (sow outdoors) | Oct 2–30 (transplant) Sep 18–Oct 16 (sowing) |
| Broccoli | Nov 7–21 | Dec 19–Jan 2 (transplant) | Sep 18–Oct 16 (transplant) |
| Cabbage | Nov 7–21 | Dec 19–Jan 2 (transplant) | Sep 18–Oct 16 (transplant) |
| Cauliflower | Nov 7–21 | Jan 2–16 (transplant) | Sep 18–Oct 16 (transplant) |
| Brussels sprouts | Oct 24–Nov 7 | Dec 19–Jan 2 (transplant) | Sep 4–25 (transplant) |
| Kohlrabi | Nov 21–Dec 5 | Dec 19–Jan 2 (transplant) Dec 19–Jan 2 (sow outdoors) | Oct 16–30 (sowing) |
| Bok choy / Asian greens | – | Dec 19–Jan 2 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Arugula | – | Dec 19–Jan 16 (sow outdoors) | Oct 30–Nov 27 (sowing) |
| Mustard greens | – | Dec 19–Jan 9 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Swiss chard | Dec 5–19 | Jan 2–23 (transplant) Jan 2–30 (sow outdoors) | Oct 16–30 (sowing) |
| Beet | – | Dec 19–Jan 16 (sow outdoors) | Oct 16–30 (sowing) |
| Carrot | – | Dec 26–Jan 23 (sow outdoors) | Oct 2–16 (sowing) |
| Radish | – | Dec 12–Jan 23 (sow outdoors) | Nov 13–27 (sowing) |
| Turnip | – | Dec 19–Jan 9 (sow outdoors) | Oct 16–30 (sowing) |
| Parsnip | – | Dec 26–Jan 16 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Nov 21–Dec 19 (sow outdoors) | Oct 2–16 (sowing) |
| Onion (bulbing) | Oct 24–Nov 7 | Dec 5–19 (transplant) | – |
| Green onion / scallion | – | Dec 5–Jan 2 (sow outdoors) | Oct 16–30 (sowing) |
| Leek | Oct 24–Nov 7 | Dec 19–Jan 2 (transplant) | – |
| Garlic | – | – | Nov 13–Dec 11 (sowing) |
| Shallot | – | Dec 5–19 (transplant) | Nov 13–Dec 11 (sowing) |
| Potato | – | Dec 19–Jan 2 (transplant) | Sep 4–18 (transplant) |
| Sweet potato | – | Feb 6–20 (transplant) | – |
| Sweet corn | – | Jan 23–Feb 6 (sow outdoors) | – |
| Bean, bush (snap) | – | Jan 23–Feb 6 (sow outdoors) | Oct 2–16 (sowing) |
| Bean, pole | – | Jan 23–Feb 6 (sow outdoors) | – |
| Lima bean | – | Jan 30–Feb 13 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Feb 6–27 (sow outdoors) | – |
| Cucumber | Dec 19–26 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | Oct 2–16 (sowing) |
| Summer squash / zucchini | Dec 19–26 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | Oct 2–16 (sowing) |
| Winter squash | Dec 19–26 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | – |
| Pumpkin | – | Jan 23–Feb 6 (sow outdoors) | – |
| Watermelon | Dec 19–26 | Jan 30–Feb 13 (transplant) Jan 30–Feb 13 (sow outdoors) | – |
| Cantaloupe / muskmelon | Dec 19–26 | Jan 30–Feb 13 (transplant) Jan 30–Feb 13 (sow outdoors) | – |
| Okra | Dec 5–19 | Jan 30–Feb 13 (transplant) Jan 30–Feb 13 (sow outdoors) | – |
| Celery | Oct 24–Nov 7 | Jan 23–30 (transplant) | – |
| Basil | Dec 5–19 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | – |
| Cilantro | – | Jan 2–30 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Parsley | Nov 7–21 | Jan 2–16 (transplant) Dec 26–Jan 16 (sow outdoors) | – |
| Dill | – | Jan 16–30 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Sunflower | – | Jan 16–30 (sow outdoors) | – |
| Asparagus (crowns) | – | Dec 19–Jan 2 (transplant) | – |
| Rhubarb (crowns) | – | Dec 19–Jan 2 (transplant) | – |
| Strawberry (plants) | – | Dec 19–Jan 2 (transplant) | Oct 16–Nov 13 (transplant) |
Typical ranges from university extension planting calendars, adjusted to your frost dates. Probabilities, not guarantees. Fall windows that would overlap spring planting are left out, as are fall crops of frost-tender plants where the frost-free season is under 210 days.
Where these numbers come from
Station: San Luis Obispo Poly, CA (NOAA GHCN-Daily ID USC00047851), elevation 308 ft, 0.3 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| San Luis Obispo AP, CA | 5 mi | Jan 31 | Dec 11 |
| Pismo Beach, CA | 10 mi | Feb 1 | Jan 4 (next year) |
| Morro Bay Fire Dept, CA | 11 mi | Jan 19 | Jan 14 (next year) |
The average last-frost dates of these stations span 16 days, a rough guide to local variation. See data sources & methods.
Frost questions for 93410
When is the last frost in 93410?
The average (50% chance) last spring freeze of 32°F for ZIP 93410 is January 16. For a more cautious planting date, use February 26, when only 1 year in 10 still sees a later freeze.
When is the first frost in 93410?
The average first fall freeze is December 25. In 1 year in 10 it comes by November 25.
What hardiness zone is 93410?
ZIP 93410 is in USDA zone 9b (25 to 30°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 93410 right now?
This page shows the latest 2-inch and 4-inch soil temperature from the nearest public soil station (USDA SCAN, NOAA USCRN or TexMesonet), or a labeled estimate when no station is close, against the 50–55°F spring pre-emergent band.
Nearby ZIP codes
93407 California Polytechnic State University 93409 93408 93405 San Luis Obispo 93401 San Luis Obispo 93449 Pismo Beach 93402 Los Osos 93424 Avila Beach
Other ZIP codes in San Luis Obispo County
93401 93402 93405 93407 93408 93409 93420 93422 93424 93428 93430 93432 93433 93442 93444 93445 93446 93449 93452 93453 93461 93465 All San Luis Obispo County frost dates · California frost dates
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- Freeze alerts
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Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.