Fall in zone 9bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 92304 (San Bernardino County, 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, Mitchell Caverns, CA (28 miles away).
Station is a bit far
The nearest station with freeze normals is over 40 km away, so dates here may be off by a week or more.
- Average last spring frostMar 650% chance of a 32°F freeze after this date
- Average first fall frostDec 850% chance of a 32°F freeze by this date
- Growing season (frost-free)272 daysmedian, 32°F threshold
- USDA hardiness zone9b25 to 30°F avg. coldest night
Get The Dial for 92304
Frost and freeze alerts from the NWS forecast for 92304, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.
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
69°F 55°F or warmer
24-hour average · latest 66°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Essex (31 mi), Desert Center (56 mi).
4-inch depth
70°F 55°F or warmer
24-hour average · latest 69°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Essex (31 mi), Desert Center (56 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 92304 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 70°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): window open as soil cools through the 70s and 60s.
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 Apr 21 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 Sep 29–Oct 27
- Lettuce: fall transplant Oct 13–Nov 3
- Spinach: fall sowing Oct 13–Nov 3
- Bok choy / Asian greens: fall sowing Oct 13–27
- Arugula: fall sowing Oct 13–Nov 10
- Mustard greens: fall sowing Oct 13–27
- Cilantro: fall sowing Oct 13–27
- Dill: fall sowing Oct 13–27
- Strawberry (plants): fall transplant Sep 29–Oct 27
Coming up in the next 3 weeks
- Radish: fall sowing Oct 27–Nov 10
- Garlic: fall sowing Oct 27–Nov 24
- Shallot: fall sowing Oct 27–Nov 24
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Dec 8: skip heavy pruning in the 6–8 weeks before it, because new growth may not harden off in time.
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) | Jan 17 |
| 50% (the "average" last frost) | Mar 6 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 9 |
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 12 |
| 50% (the "average" first frost) | Dec 8 |
| 90% (late: most years have frozen by now) | Jan 5 (next year) |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 1 | Nov 24 |
| 32°F (freeze) | Mar 6 | Dec 8 |
| 28°F (hard freeze) | Feb 1 | Dec 25 |
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 92304
Dates count from your average last spring frost (Mar 6) and first fall frost (Dec 8). 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 | Jan 9–23 | Mar 13–27 (transplant) | Aug 11–Sep 8 (transplant) |
| Pepper (sweet and hot) | Dec 26–Jan 9 | Mar 20–Apr 3 (transplant) | Aug 18–Sep 8 (transplant) |
| Eggplant | Dec 26–Jan 9 | Mar 20–Apr 3 (transplant) | Aug 18–Sep 8 (transplant) |
| Tomatillo | Jan 9–23 | Mar 13–27 (transplant) | – |
| Lettuce | Jan 9–23 | Feb 13–Mar 6 (transplant) Feb 6–Mar 20 (sow outdoors) | Oct 13–Nov 3 (transplant) Sep 29–Oct 27 (sowing) |
| Spinach | – | Jan 23–Feb 13 (sow outdoors) | Oct 13–Nov 3 (sowing) |
| Kale | Jan 9–23 | Feb 6–20 (transplant) Feb 6–20 (sow outdoors) | Sep 15–Oct 13 (transplant) Sep 1–29 (sowing) |
| Collards | Jan 9–23 | Feb 6–Mar 6 (transplant) Feb 6–Mar 6 (sow outdoors) | Sep 15–Oct 13 (transplant) Sep 1–29 (sowing) |
| Broccoli | Dec 26–Jan 9 | Feb 6–20 (transplant) | Sep 1–29 (transplant) |
| Cabbage | Dec 26–Jan 9 | Feb 6–20 (transplant) | Sep 1–29 (transplant) |
| Cauliflower | Dec 26–Jan 9 | Feb 20–Mar 6 (transplant) | Sep 1–29 (transplant) |
| Brussels sprouts | Dec 12–26 | Feb 6–20 (transplant) | Aug 18–Sep 8 (transplant) |
| Kohlrabi | Jan 9–23 | Feb 6–20 (transplant) Feb 6–20 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Bok choy / Asian greens | – | Feb 6–20 (sow outdoors) | Oct 13–27 (sowing) |
| Arugula | – | Feb 6–Mar 6 (sow outdoors) | Oct 13–Nov 10 (sowing) |
| Mustard greens | – | Feb 6–27 (sow outdoors) | Oct 13–27 (sowing) |
| Swiss chard | Jan 23–Feb 6 | Feb 20–Mar 13 (transplant) Feb 20–Mar 20 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Beet | – | Feb 6–Mar 6 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Carrot | – | Feb 13–Mar 13 (sow outdoors) | Sep 15–29 (sowing) |
| Radish | – | Jan 30–Mar 13 (sow outdoors) | Oct 27–Nov 10 (sowing) |
| Turnip | – | Feb 6–27 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Parsnip | – | Feb 13–Mar 6 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 9–Feb 6 (sow outdoors) | Sep 15–29 (sowing) |
| Onion (bulbing) | Dec 12–26 | Jan 23–Feb 6 (transplant) | – |
| Green onion / scallion | – | Jan 23–Feb 20 (sow outdoors) | Sep 29–Oct 13 (sowing) |
| Leek | Dec 12–26 | Feb 6–20 (transplant) | – |
| Garlic | – | – | Oct 27–Nov 24 (sowing) |
| Shallot | – | Jan 23–Feb 6 (transplant) | Oct 27–Nov 24 (sowing) |
| Potato | – | Feb 6–20 (transplant) | Aug 18–Sep 1 (transplant) |
| Sweet potato | – | Mar 27–Apr 10 (transplant) | – |
| Sweet corn | – | Mar 13–27 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 13–27 (sow outdoors) | Sep 15–29 (sowing) |
| Bean, pole | – | Mar 13–27 (sow outdoors) | – |
| Lima bean | – | Mar 20–Apr 3 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Mar 27–Apr 17 (sow outdoors) | – |
| Cucumber | Feb 6–13 | Mar 13–27 (transplant) Mar 13–27 (sow outdoors) | Sep 15–29 (sowing) |
| Summer squash / zucchini | Feb 6–13 | Mar 13–27 (transplant) Mar 13–27 (sow outdoors) | Sep 15–29 (sowing) |
| Winter squash | Feb 6–13 | Mar 13–27 (transplant) Mar 13–27 (sow outdoors) | – |
| Pumpkin | – | Mar 13–27 (sow outdoors) | – |
| Watermelon | Feb 6–13 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | – |
| Cantaloupe / muskmelon | Feb 6–13 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | – |
| Okra | Jan 23–Feb 6 | Mar 20–Apr 3 (transplant) Mar 20–Apr 3 (sow outdoors) | – |
| Celery | Dec 12–26 | Mar 13–20 (transplant) | – |
| Basil | Jan 23–Feb 6 | Mar 13–27 (transplant) Mar 13–27 (sow outdoors) | – |
| Cilantro | – | Feb 20–Mar 20 (sow outdoors) | Oct 13–27 (sowing) |
| Parsley | Dec 26–Jan 9 | Feb 20–Mar 6 (transplant) Feb 13–Mar 6 (sow outdoors) | – |
| Dill | – | Mar 6–20 (sow outdoors) | Oct 13–27 (sowing) |
| Sunflower | – | Mar 6–20 (sow outdoors) | – |
| Asparagus (crowns) | – | Feb 6–20 (transplant) | – |
| Rhubarb (crowns) | – | Feb 6–20 (transplant) | – |
| Strawberry (plants) | – | Feb 6–20 (transplant) | Sep 29–Oct 27 (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: Mitchell Caverns, CA (NOAA GHCN-Daily ID USC00045721), elevation 4,350 ft, 28.5 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Twentynine Palms, CA | 35 mi | Jan 24 | Dec 10 |
| Iron Mtn, CA | 43 mi | Jan 3 | Dec 31 |
| Joshua Tree, CA | 43 mi | Feb 28 | Dec 1 |
The average last-frost dates of these stations span 65 days, a rough guide to local variation. See data sources & methods.
Frost questions for 92304
When is the last frost in 92304?
The average (50% chance) last spring freeze of 32°F for ZIP 92304 is March 6. For a more cautious planting date, use April 9, when only 1 year in 10 still sees a later freeze.
When is the first frost in 92304?
The average first fall freeze is December 8. In 1 year in 10 it comes by November 12.
What hardiness zone is 92304?
ZIP 92304 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 92304 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
92277 Twentynine Palms 92278 Twentynine Palms 92332 92338 92252 Joshua Tree 92285 Homestead Valley 92280 92284 Yucca Valley
Other ZIP codes in San Bernardino County
91701 91708 91709 91710 91730 91737 91739 91761 91762 91763 91764 91784 91786 92242 92252 92256 92267 92268 92277 92278 92280 92284 92285 92301 All San Bernardino County frost dates · California frost dates
Never miss a frost: get The Dial
Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.