Fall in zone 10aPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 91935 (Jamul, 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, Alpine, CA (10 miles away).
- Average last spring frostFeb 1250% chance of a 32°F freeze after this date
- Average first fall frostDec 2450% chance of a 32°F freeze by this date
- Growing season (frost-free)317 daysmedian, 32°F threshold
- USDA hardiness zone10a30 to 35°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
Soil temperature now
2-inch depth
77°F 55°F or warmer
24-hour average · latest 73°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Fallbrook 5 NE (57 mi).
4-inch depth
78°F 55°F or warmer
24-hour average · latest 76°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Fallbrook 5 NE (57 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 91935 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 78°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 30 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 15–Nov 12
- Kale: fall transplant Oct 1–29
- Collards: fall transplant Oct 1–29
- Kohlrabi: fall sowing Oct 15–29
- Swiss chard: fall sowing Oct 15–29
- Beet: fall sowing Oct 15–29
- Turnip: fall sowing Oct 15–29
- Green onion / scallion: fall sowing Oct 15–29
- Strawberry (plants): fall transplant Oct 15–Nov 12
Coming up in the next 3 weeks
- Lettuce: fall transplant Oct 29–Nov 19
- Spinach: fall sowing Oct 29–Nov 19
- Bok choy / Asian greens: fall sowing Oct 29–Nov 12
- Arugula: fall sowing Oct 29–Nov 26
- Mustard greens: fall sowing Oct 29–Nov 12
- Cilantro: fall sowing Oct 29–Nov 12
- Dill: fall sowing Oct 29–Nov 12
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 29 (prior Dec) |
| 50% (the "average" last frost) | Feb 12 |
| 10% (cautious: only 1 year in 10 freezes later) | Mar 20 |
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) | Dec 2 |
| 50% (the "average" first frost) | Dec 24 |
| 90% (late: most years have frozen by now) | Feb 3 (next year) |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Mar 17 | Dec 7 |
| 32°F (freeze) | Feb 12 | Dec 24 |
| 28°F (hard freeze) | Jan 22 | Jan 4 (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 91935
Dates count from your average last spring frost (Feb 12) and first fall frost (Dec 24). 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 | Dec 18–Jan 1 | Feb 19–Mar 5 (transplant) | Aug 27–Sep 24 (transplant) |
| Pepper (sweet and hot) | Dec 4–18 | Feb 26–Mar 12 (transplant) | Sep 3–24 (transplant) |
| Eggplant | Dec 4–18 | Feb 26–Mar 12 (transplant) | Sep 3–24 (transplant) |
| Tomatillo | Dec 18–Jan 1 | Feb 19–Mar 5 (transplant) | – |
| Lettuce | Dec 18–Jan 1 | Jan 22–Feb 12 (transplant) Jan 15–Feb 26 (sow outdoors) | Oct 29–Nov 19 (transplant) Oct 15–Nov 12 (sowing) |
| Spinach | – | Jan 1–22 (sow outdoors) | Oct 29–Nov 19 (sowing) |
| Kale | Dec 18–Jan 1 | Jan 15–29 (transplant) Jan 15–29 (sow outdoors) | Oct 1–29 (transplant) Sep 17–Oct 15 (sowing) |
| Collards | Dec 18–Jan 1 | Jan 15–Feb 12 (transplant) Jan 15–Feb 12 (sow outdoors) | Oct 1–29 (transplant) Sep 17–Oct 15 (sowing) |
| Broccoli | Dec 4–18 | Jan 15–29 (transplant) | Sep 17–Oct 15 (transplant) |
| Cabbage | Dec 4–18 | Jan 15–29 (transplant) | Sep 17–Oct 15 (transplant) |
| Cauliflower | Dec 4–18 | Jan 29–Feb 12 (transplant) | Sep 17–Oct 15 (transplant) |
| Brussels sprouts | Nov 20–Dec 4 | Jan 15–29 (transplant) | Sep 3–24 (transplant) |
| Kohlrabi | Dec 18–Jan 1 | Jan 15–29 (transplant) Jan 15–29 (sow outdoors) | Oct 15–29 (sowing) |
| Bok choy / Asian greens | – | Jan 15–29 (sow outdoors) | Oct 29–Nov 12 (sowing) |
| Arugula | – | Jan 15–Feb 12 (sow outdoors) | Oct 29–Nov 26 (sowing) |
| Mustard greens | – | Jan 15–Feb 5 (sow outdoors) | Oct 29–Nov 12 (sowing) |
| Swiss chard | Jan 1–15 | Jan 29–Feb 19 (transplant) Jan 29–Feb 26 (sow outdoors) | Oct 15–29 (sowing) |
| Beet | – | Jan 15–Feb 12 (sow outdoors) | Oct 15–29 (sowing) |
| Carrot | – | Jan 22–Feb 19 (sow outdoors) | Oct 1–15 (sowing) |
| Radish | – | Jan 8–Feb 19 (sow outdoors) | Nov 12–26 (sowing) |
| Turnip | – | Jan 15–Feb 5 (sow outdoors) | Oct 15–29 (sowing) |
| Parsnip | – | Jan 22–Feb 12 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Dec 18–Jan 15 (sow outdoors) | Oct 1–15 (sowing) |
| Onion (bulbing) | Nov 20–Dec 4 | Jan 1–15 (transplant) | – |
| Green onion / scallion | – | Jan 1–29 (sow outdoors) | Oct 15–29 (sowing) |
| Leek | Nov 20–Dec 4 | Jan 15–29 (transplant) | – |
| Garlic | – | – | Nov 12–Dec 10 (sowing) |
| Shallot | – | Jan 1–15 (transplant) | Nov 12–Dec 10 (sowing) |
| Potato | – | Jan 15–29 (transplant) | Sep 3–17 (transplant) |
| Sweet potato | – | Mar 5–19 (transplant) | – |
| Sweet corn | – | Feb 19–Mar 5 (sow outdoors) | – |
| Bean, bush (snap) | – | Feb 19–Mar 5 (sow outdoors) | Oct 1–15 (sowing) |
| Bean, pole | – | Feb 19–Mar 5 (sow outdoors) | – |
| Lima bean | – | Feb 26–Mar 12 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Mar 5–26 (sow outdoors) | – |
| Cucumber | Jan 15–22 | Feb 19–Mar 5 (transplant) Feb 19–Mar 5 (sow outdoors) | Oct 1–15 (sowing) |
| Summer squash / zucchini | Jan 15–22 | Feb 19–Mar 5 (transplant) Feb 19–Mar 5 (sow outdoors) | Oct 1–15 (sowing) |
| Winter squash | Jan 15–22 | Feb 19–Mar 5 (transplant) Feb 19–Mar 5 (sow outdoors) | – |
| Pumpkin | – | Feb 19–Mar 5 (sow outdoors) | – |
| Watermelon | Jan 15–22 | Feb 26–Mar 12 (transplant) Feb 26–Mar 12 (sow outdoors) | – |
| Cantaloupe / muskmelon | Jan 15–22 | Feb 26–Mar 12 (transplant) Feb 26–Mar 12 (sow outdoors) | – |
| Okra | Jan 1–15 | Feb 26–Mar 12 (transplant) Feb 26–Mar 12 (sow outdoors) | – |
| Celery | Nov 20–Dec 4 | Feb 19–26 (transplant) | – |
| Basil | Jan 1–15 | Feb 19–Mar 5 (transplant) Feb 19–Mar 5 (sow outdoors) | – |
| Cilantro | – | Jan 29–Feb 26 (sow outdoors) | Oct 29–Nov 12 (sowing) |
| Parsley | Dec 4–18 | Jan 29–Feb 12 (transplant) Jan 22–Feb 12 (sow outdoors) | – |
| Dill | – | Feb 12–26 (sow outdoors) | Oct 29–Nov 12 (sowing) |
| Sunflower | – | Feb 12–26 (sow outdoors) | – |
| Asparagus (crowns) | – | Jan 15–29 (transplant) | – |
| Rhubarb (crowns) | – | Jan 15–29 (transplant) | – |
| Strawberry (plants) | – | Jan 15–29 (transplant) | Oct 15–Nov 12 (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: Alpine, CA (NOAA GHCN-Daily ID USC00040136), elevation 1,695 ft, 9.8 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| El Cajon, CA | 11 mi | Jan 6 | Dec 21 |
| El Capitan Dam, CA | 13 mi | Mar 19 | Dec 8 |
| San Diego Brown Fld, CA | 15 mi | Jan 6 | Dec 31 |
The average last-frost dates of these stations span 75 days, a rough guide to local variation. See data sources & methods.
Frost questions for 91935
When is the last frost in 91935?
The average (50% chance) last spring freeze of 32°F for ZIP 91935 is February 12. For a more cautious planting date, use March 20, when only 1 year in 10 still sees a later freeze.
When is the first frost in 91935?
The average first fall freeze is December 24. In 1 year in 10 it comes by December 2.
What hardiness zone is 91935?
ZIP 91935 is in USDA zone 10a (30 to 35°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 91935 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
91917 92019 Rancho San Diego 91901 Alpine 91978 Spring Valley 91914 Chula Vista 91963 Potrero 91980 91915 Chula Vista
Other ZIP codes in San Diego County
91901 91902 91905 91906 91910 91911 91913 91914 91915 91916 91917 91931 91932 91934 91941 91942 91945 91948 91950 91962 91963 91977 91978 91980 All San Diego 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.