Fall in zone 9aPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 94928 (Rohnert Park, 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, Petaluma AP, CA (8 miles away).
- Average last spring frostFeb 2850% chance of a 32°F freeze after this date
- Average first fall frostNov 2550% chance of a 32°F freeze by this date
- Growing season (frost-free)271 daysmedian, 32°F threshold
- USDA hardiness zone9a20 to 25°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
No soil station with a fresh reading within 62 miles.
4-inch depth
No soil station with a fresh reading within 62 miles.
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 94928 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
No soil reading near this ZIP. Typical extension timing for your region: spring February to March; fall 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 Apr 15 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 transplant Sep 30–Oct 21
- Spinach: fall sowing Sep 30–Oct 21
- Arugula: fall sowing Sep 30–Oct 28
- Radish: fall sowing Oct 14–28
- Garlic: fall sowing Oct 14–Nov 11
- Shallot: fall sowing Oct 14–Nov 11
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Nov 25: 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 24 |
| 50% (the "average" last frost) | Feb 28 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 6 |
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 9 |
| 50% (the "average" first frost) | Nov 25 |
| 90% (late: most years have frozen by now) | Dec 16 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Apr 6 | Nov 10 |
| 32°F (freeze) | Feb 28 | Nov 25 |
| 28°F (hard freeze) | Jan 17 | Dec 9 |
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 94928
Dates count from your average last spring frost (Feb 28) and first fall frost (Nov 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 | Jan 3–17 | Mar 7–21 (transplant) | Jul 29–Aug 26 (transplant) |
| Pepper (sweet and hot) | Dec 20–Jan 3 | Mar 14–28 (transplant) | Aug 5–26 (transplant) |
| Eggplant | Dec 20–Jan 3 | Mar 14–28 (transplant) | Aug 5–26 (transplant) |
| Tomatillo | Jan 3–17 | Mar 7–21 (transplant) | – |
| Lettuce | Jan 3–17 | Feb 7–28 (transplant) Jan 31–Mar 14 (sow outdoors) | Sep 30–Oct 21 (transplant) Sep 16–Oct 14 (sowing) |
| Spinach | – | Jan 17–Feb 7 (sow outdoors) | Sep 30–Oct 21 (sowing) |
| Kale | Jan 3–17 | Jan 31–Feb 14 (transplant) Jan 31–Feb 14 (sow outdoors) | Sep 2–30 (transplant) Aug 19–Sep 16 (sowing) |
| Collards | Jan 3–17 | Jan 31–Feb 28 (transplant) Jan 31–Feb 28 (sow outdoors) | Sep 2–30 (transplant) Aug 19–Sep 16 (sowing) |
| Broccoli | Dec 20–Jan 3 | Jan 31–Feb 14 (transplant) | Aug 19–Sep 16 (transplant) |
| Cabbage | Dec 20–Jan 3 | Jan 31–Feb 14 (transplant) | Aug 19–Sep 16 (transplant) |
| Cauliflower | Dec 20–Jan 3 | Feb 14–28 (transplant) | Aug 19–Sep 16 (transplant) |
| Brussels sprouts | Dec 6–20 | Jan 31–Feb 14 (transplant) | Aug 5–26 (transplant) |
| Kohlrabi | Jan 3–17 | Jan 31–Feb 14 (transplant) Jan 31–Feb 14 (sow outdoors) | Sep 16–30 (sowing) |
| Bok choy / Asian greens | – | Jan 31–Feb 14 (sow outdoors) | Sep 30–Oct 14 (sowing) |
| Arugula | – | Jan 31–Feb 28 (sow outdoors) | Sep 30–Oct 28 (sowing) |
| Mustard greens | – | Jan 31–Feb 21 (sow outdoors) | Sep 30–Oct 14 (sowing) |
| Swiss chard | Jan 17–31 | Feb 14–Mar 7 (transplant) Feb 14–Mar 14 (sow outdoors) | Sep 16–30 (sowing) |
| Beet | – | Jan 31–Feb 28 (sow outdoors) | Sep 16–30 (sowing) |
| Carrot | – | Feb 7–Mar 7 (sow outdoors) | Sep 2–16 (sowing) |
| Radish | – | Jan 24–Mar 7 (sow outdoors) | Oct 14–28 (sowing) |
| Turnip | – | Jan 31–Feb 21 (sow outdoors) | Sep 16–30 (sowing) |
| Parsnip | – | Feb 7–28 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Jan 3–31 (sow outdoors) | Sep 2–16 (sowing) |
| Onion (bulbing) | Dec 6–20 | Jan 17–31 (transplant) | – |
| Green onion / scallion | – | Jan 17–Feb 14 (sow outdoors) | Sep 16–30 (sowing) |
| Leek | Dec 6–20 | Jan 31–Feb 14 (transplant) | – |
| Garlic | – | – | Oct 14–Nov 11 (sowing) |
| Shallot | – | Jan 17–31 (transplant) | Oct 14–Nov 11 (sowing) |
| Potato | – | Jan 31–Feb 14 (transplant) | Aug 5–19 (transplant) |
| Sweet potato | – | Mar 21–Apr 4 (transplant) | – |
| Sweet corn | – | Mar 7–21 (sow outdoors) | – |
| Bean, bush (snap) | – | Mar 7–21 (sow outdoors) | Sep 2–16 (sowing) |
| Bean, pole | – | Mar 7–21 (sow outdoors) | – |
| Lima bean | – | Mar 14–28 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Mar 21–Apr 11 (sow outdoors) | – |
| Cucumber | Jan 31–Feb 7 | Mar 7–21 (transplant) Mar 7–21 (sow outdoors) | Sep 2–16 (sowing) |
| Summer squash / zucchini | Jan 31–Feb 7 | Mar 7–21 (transplant) Mar 7–21 (sow outdoors) | Sep 2–16 (sowing) |
| Winter squash | Jan 31–Feb 7 | Mar 7–21 (transplant) Mar 7–21 (sow outdoors) | – |
| Pumpkin | – | Mar 7–21 (sow outdoors) | – |
| Watermelon | Jan 31–Feb 7 | Mar 14–28 (transplant) Mar 14–28 (sow outdoors) | – |
| Cantaloupe / muskmelon | Jan 31–Feb 7 | Mar 14–28 (transplant) Mar 14–28 (sow outdoors) | – |
| Okra | Jan 17–31 | Mar 14–28 (transplant) Mar 14–28 (sow outdoors) | – |
| Celery | Dec 6–20 | Mar 7–14 (transplant) | – |
| Basil | Jan 17–31 | Mar 7–21 (transplant) Mar 7–21 (sow outdoors) | – |
| Cilantro | – | Feb 14–Mar 14 (sow outdoors) | Sep 30–Oct 14 (sowing) |
| Parsley | Dec 20–Jan 3 | Feb 14–28 (transplant) Feb 7–28 (sow outdoors) | – |
| Dill | – | Feb 28–Mar 14 (sow outdoors) | Sep 30–Oct 14 (sowing) |
| Sunflower | – | Feb 28–Mar 14 (sow outdoors) | – |
| Asparagus (crowns) | – | Jan 31–Feb 14 (transplant) | – |
| Rhubarb (crowns) | – | Jan 31–Feb 14 (transplant) | – |
| Strawberry (plants) | – | Jan 31–Feb 14 (transplant) | Sep 16–Oct 14 (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: Petaluma AP, CA (NOAA GHCN-Daily ID USC00046826), elevation 20 ft, 7.6 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Santa Rosa, CA | 8 mi | Feb 25 | Dec 1 |
| Graton, CA | 11 mi | Mar 20 | Nov 13 |
| Santa Rosa Sonoma Co AP, CA | 13 mi | Mar 2 | Nov 20 |
The average last-frost dates of these stations span 26 days, a rough guide to local variation. See data sources & methods.
Frost questions for 94928
When is the last frost in 94928?
The average (50% chance) last spring freeze of 32°F for ZIP 94928 is February 28. For a more cautious planting date, use April 6, when only 1 year in 10 still sees a later freeze.
When is the first frost in 94928?
The average first fall freeze is November 25. In 1 year in 10 it comes by November 9.
What hardiness zone is 94928?
ZIP 94928 is in USDA zone 9a (20 to 25°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 94928 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
94931 Cotati 94951 Penngrove 95407 Santa Rosa 95405 Santa Rosa 94952 Bloomfield 95401 Santa Rosa 95431 95472 Occidental
Other ZIP codes in Sonoma County
94515 94922 94923 94931 94951 94954 94972 95401 95403 95404 95405 95407 95409 95412 95419 95421 95425 95430 95431 95436 95439 95441 95442 95444 All Sonoma County frost dates · California frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- 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.