Fall in zone 9bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 92508 (Riverside, 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, Riverside Fire STN 3, CA (5 miles away).
Freezes are uncommon here
NOAA's normals for this station show a 32°F night in about 69% of years (about 2 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 950% 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)353 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
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 (32 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 (32 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 92508 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 Feb 24 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
- Brussels sprouts: start seeds indoors Oct 17–31
- 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
- Onion (bulbing): start seeds indoors Oct 17–31
- Green onion / scallion: fall sowing Oct 16–30
- Leek: start seeds indoors Oct 17–31
- Celery: start seeds indoors Oct 17–31
- Strawberry (plants): fall transplant Oct 16–Nov 13
Coming up in the next 3 weeks
- Pepper (sweet and hot): start seeds indoors Oct 31–Nov 14
- Eggplant: start seeds indoors Oct 31–Nov 14
- Lettuce: fall transplant Oct 30–Nov 20
- Spinach: fall sowing Oct 30–Nov 20
- Broccoli: start seeds indoors Oct 31–Nov 14
- Cabbage: start seeds indoors Oct 31–Nov 14
- Cauliflower: start seeds indoors Oct 31–Nov 14
- 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
- Cilantro: fall sowing Oct 30–Nov 13
- Parsley: start seeds indoors Oct 31–Nov 14
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 16 (prior Dec) |
| 50% (the "average" last frost) | Jan 9 |
| 10% (cautious: only 1 year in 10 freezes later) | Feb 25 |
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 1 |
| 50% (the "average" first frost) | Dec 25 |
| 90% (late: most years have frozen by now) | Jan 27 (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 19 | Dec 6 |
| 32°F (freeze) | Jan 9 | Dec 25 |
| 28°F (hard freeze) | Dec 31 (prior Dec) | Dec 29 |
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 92508
Dates count from your average last spring frost (Jan 9) 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 14–28 | Jan 16–30 (transplant) | Aug 28–Sep 25 (transplant) |
| Pepper (sweet and hot) | Oct 31–Nov 14 | Jan 23–Feb 6 (transplant) | Sep 4–25 (transplant) |
| Eggplant | Oct 31–Nov 14 | Jan 23–Feb 6 (transplant) | Sep 4–25 (transplant) |
| Tomatillo | Nov 14–28 | Jan 16–30 (transplant) | – |
| Lettuce | Nov 14–28 | Dec 19–Jan 9 (transplant) Dec 12–Jan 23 (sow outdoors) | Oct 30–Nov 20 (transplant) Oct 16–Nov 13 (sowing) |
| Spinach | – | Nov 28–Dec 19 (sow outdoors) | Oct 30–Nov 20 (sowing) |
| Kale | Nov 14–28 | Dec 12–26 (transplant) Dec 12–26 (sow outdoors) | Oct 2–30 (transplant) Sep 18–Oct 16 (sowing) |
| Collards | Nov 14–28 | Dec 12–Jan 9 (transplant) Dec 12–Jan 9 (sow outdoors) | Oct 2–30 (transplant) Sep 18–Oct 16 (sowing) |
| Broccoli | Oct 31–Nov 14 | Dec 12–26 (transplant) | Sep 18–Oct 16 (transplant) |
| Cabbage | Oct 31–Nov 14 | Dec 12–26 (transplant) | Sep 18–Oct 16 (transplant) |
| Cauliflower | Oct 31–Nov 14 | Dec 26–Jan 9 (transplant) | Sep 18–Oct 16 (transplant) |
| Brussels sprouts | Oct 17–31 | Dec 12–26 (transplant) | Sep 4–25 (transplant) |
| Kohlrabi | Nov 14–28 | Dec 12–26 (transplant) Dec 12–26 (sow outdoors) | Oct 16–30 (sowing) |
| Bok choy / Asian greens | – | Dec 12–26 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Arugula | – | Dec 12–Jan 9 (sow outdoors) | Oct 30–Nov 27 (sowing) |
| Mustard greens | – | Dec 12–Jan 2 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Swiss chard | Nov 28–Dec 12 | Dec 26–Jan 16 (transplant) Dec 26–Jan 23 (sow outdoors) | Oct 16–30 (sowing) |
| Beet | – | Dec 12–Jan 9 (sow outdoors) | Oct 16–30 (sowing) |
| Carrot | – | Dec 19–Jan 16 (sow outdoors) | Oct 2–16 (sowing) |
| Radish | – | Dec 5–Jan 16 (sow outdoors) | Nov 13–27 (sowing) |
| Turnip | – | Dec 12–Jan 2 (sow outdoors) | Oct 16–30 (sowing) |
| Parsnip | – | Dec 19–Jan 9 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Nov 14–Dec 12 (sow outdoors) | Oct 2–16 (sowing) |
| Onion (bulbing) | Oct 17–31 | Nov 28–Dec 12 (transplant) | – |
| Green onion / scallion | – | Nov 28–Dec 26 (sow outdoors) | Oct 16–30 (sowing) |
| Leek | Oct 17–31 | Dec 12–26 (transplant) | – |
| Garlic | – | – | Nov 13–Dec 11 (sowing) |
| Shallot | – | Nov 28–Dec 12 (transplant) | Nov 13–Dec 11 (sowing) |
| Potato | – | Dec 12–26 (transplant) | Sep 4–18 (transplant) |
| Sweet potato | – | Jan 30–Feb 13 (transplant) | – |
| Sweet corn | – | Jan 16–30 (sow outdoors) | – |
| Bean, bush (snap) | – | Jan 16–30 (sow outdoors) | Oct 2–16 (sowing) |
| Bean, pole | – | Jan 16–30 (sow outdoors) | – |
| Lima bean | – | Jan 23–Feb 6 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jan 30–Feb 20 (sow outdoors) | – |
| Cucumber | Dec 12–19 | Jan 16–30 (transplant) Jan 16–30 (sow outdoors) | Oct 2–16 (sowing) |
| Summer squash / zucchini | Dec 12–19 | Jan 16–30 (transplant) Jan 16–30 (sow outdoors) | Oct 2–16 (sowing) |
| Winter squash | Dec 12–19 | Jan 16–30 (transplant) Jan 16–30 (sow outdoors) | – |
| Pumpkin | – | Jan 16–30 (sow outdoors) | – |
| Watermelon | Dec 12–19 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | – |
| Cantaloupe / muskmelon | Dec 12–19 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | – |
| Okra | Nov 28–Dec 12 | Jan 23–Feb 6 (transplant) Jan 23–Feb 6 (sow outdoors) | – |
| Celery | Oct 17–31 | Jan 16–23 (transplant) | – |
| Basil | Nov 28–Dec 12 | Jan 16–30 (transplant) Jan 16–30 (sow outdoors) | – |
| Cilantro | – | Dec 26–Jan 23 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Parsley | Oct 31–Nov 14 | Dec 26–Jan 9 (transplant) Dec 19–Jan 9 (sow outdoors) | – |
| Dill | – | Jan 9–23 (sow outdoors) | Oct 30–Nov 13 (sowing) |
| Sunflower | – | Jan 9–23 (sow outdoors) | – |
| Asparagus (crowns) | – | Dec 12–26 (transplant) | – |
| Rhubarb (crowns) | – | Dec 12–26 (transplant) | – |
| Strawberry (plants) | – | Dec 12–26 (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: Riverside Fire STN 3, CA (NOAA GHCN-Daily ID USC00047470), elevation 840 ft, 5.4 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Riverside Citrus EXP, CA | 6 mi | Jan 10 | Jan 2 (next year) |
| Riverside Muni AP, CA | 8 mi | Jan 9 | Dec 30 |
| Redlands, CA | 13 mi | Jan 27 | Dec 19 |
The average last-frost dates of these stations span 18 days, a rough guide to local variation. See data sources & methods.
Frost questions for 92508
When is the last frost in 92508?
The average (50% chance) last spring freeze of 32°F for ZIP 92508 is January 9. For a more cautious planting date, use February 25, when only 1 year in 10 still sees a later freeze.
When is the first frost in 92508?
The average first fall freeze is December 25. In 1 year in 10 it comes by December 1.
What hardiness zone is 92508?
ZIP 92508 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 92508 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
92518 March ARB 92506 Riverside 92504 Riverside 92553 Moreno Valley 92521 Riverside 92551 Moreno Valley 92557 Moreno Valley 92507 Riverside
Other ZIP codes in Riverside County
91752 92201 92203 92210 92211 92220 92223 92225 92230 92234 92236 92239 92240 92241 92253 92254 92258 92260 92262 92264 92270 92274 92276 92282 All Riverside 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.