Fall in zone 9bPhoto: George Chernilevsky, Public domain, via Wikimedia Commons
Frost dates for ZIP 94574 (St. Helena, 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, Angwin Pacific Union College, CA (2 miles away).
- Average last spring frostApr 750% chance of a 32°F freeze after this date
- Average first fall frostDec 550% chance of a 32°F freeze by this date
- Growing season (frost-free)245 daysmedian, 32°F threshold
- USDA hardiness zone9b25 to 30°F avg. coldest night
Get The Dial for 94574 (St. Helena)
Frost and freeze alerts from the NWS forecast for 94574, 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
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 94574 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 May 23 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 26–Oct 24
- Lettuce: fall transplant Oct 10–31
- Spinach: fall sowing Oct 10–31
- Bok choy / Asian greens: fall sowing Oct 10–24
- Arugula: fall sowing Oct 10–Nov 7
- Mustard greens: fall sowing Oct 10–24
- Cilantro: fall sowing Oct 10–24
- Dill: fall sowing Oct 10–24
- Strawberry (plants): fall transplant Sep 26–Oct 24
Coming up in the next 3 weeks
Prune now
No frost-timed pruning windows are open this week.
Your average first frost is Dec 5: 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) | Feb 23 |
| 50% (the "average" last frost) | Apr 7 |
| 10% (cautious: only 1 year in 10 freezes later) | Apr 30 |
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 14 |
| 50% (the "average" first frost) | Dec 5 |
| 90% (late: most years have frozen by now) | Jan 1 (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 30 | Nov 15 |
| 32°F (freeze) | Apr 7 | Dec 5 |
| 28°F (hard freeze) | Feb 18 | Dec 30 |
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 94574
Dates count from your average last spring frost (Apr 7) and first fall frost (Dec 5). 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 | Feb 10–24 | Apr 14–28 (transplant) | Aug 8–Sep 5 (transplant) |
| Pepper (sweet and hot) | Jan 27–Feb 10 | Apr 21–May 5 (transplant) | Aug 15–Sep 5 (transplant) |
| Eggplant | Jan 27–Feb 10 | Apr 21–May 5 (transplant) | Aug 15–Sep 5 (transplant) |
| Tomatillo | Feb 10–24 | Apr 14–28 (transplant) | – |
| Lettuce | Feb 10–24 | Mar 17–Apr 7 (transplant) Mar 10–Apr 21 (sow outdoors) | Oct 10–31 (transplant) Sep 26–Oct 24 (sowing) |
| Spinach | – | Feb 24–Mar 17 (sow outdoors) | Oct 10–31 (sowing) |
| Kale | Feb 10–24 | Mar 10–24 (transplant) Mar 10–24 (sow outdoors) | Sep 12–Oct 10 (transplant) Aug 29–Sep 26 (sowing) |
| Collards | Feb 10–24 | Mar 10–Apr 7 (transplant) Mar 10–Apr 7 (sow outdoors) | Sep 12–Oct 10 (transplant) Aug 29–Sep 26 (sowing) |
| Broccoli | Jan 27–Feb 10 | Mar 10–24 (transplant) | Aug 29–Sep 26 (transplant) |
| Cabbage | Jan 27–Feb 10 | Mar 10–24 (transplant) | Aug 29–Sep 26 (transplant) |
| Cauliflower | Jan 27–Feb 10 | Mar 24–Apr 7 (transplant) | Aug 29–Sep 26 (transplant) |
| Brussels sprouts | Jan 13–27 | Mar 10–24 (transplant) | Aug 15–Sep 5 (transplant) |
| Kohlrabi | Feb 10–24 | Mar 10–24 (transplant) Mar 10–24 (sow outdoors) | Sep 26–Oct 10 (sowing) |
| Bok choy / Asian greens | – | Mar 10–24 (sow outdoors) | Oct 10–24 (sowing) |
| Arugula | – | Mar 10–Apr 7 (sow outdoors) | Oct 10–Nov 7 (sowing) |
| Mustard greens | – | Mar 10–31 (sow outdoors) | Oct 10–24 (sowing) |
| Swiss chard | Feb 24–Mar 10 | Mar 24–Apr 14 (transplant) Mar 24–Apr 21 (sow outdoors) | Sep 26–Oct 10 (sowing) |
| Beet | – | Mar 10–Apr 7 (sow outdoors) | Sep 26–Oct 10 (sowing) |
| Carrot | – | Mar 17–Apr 14 (sow outdoors) | Sep 12–26 (sowing) |
| Radish | – | Mar 3–Apr 14 (sow outdoors) | Oct 24–Nov 7 (sowing) |
| Turnip | – | Mar 10–31 (sow outdoors) | Sep 26–Oct 10 (sowing) |
| Parsnip | – | Mar 17–Apr 7 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 10–Mar 10 (sow outdoors) | Sep 12–26 (sowing) |
| Onion (bulbing) | Jan 13–27 | Feb 24–Mar 10 (transplant) | – |
| Green onion / scallion | – | Feb 24–Mar 24 (sow outdoors) | Sep 26–Oct 10 (sowing) |
| Leek | Jan 13–27 | Mar 10–24 (transplant) | – |
| Garlic | – | – | Oct 24–Nov 21 (sowing) |
| Shallot | – | Feb 24–Mar 10 (transplant) | Oct 24–Nov 21 (sowing) |
| Potato | – | Mar 10–24 (transplant) | Aug 15–29 (transplant) |
| Sweet potato | – | Apr 28–May 12 (transplant) | – |
| Sweet corn | – | Apr 14–28 (sow outdoors) | – |
| Bean, bush (snap) | – | Apr 14–28 (sow outdoors) | Sep 12–26 (sowing) |
| Bean, pole | – | Apr 14–28 (sow outdoors) | – |
| Lima bean | – | Apr 21–May 5 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Apr 28–May 19 (sow outdoors) | – |
| Cucumber | Mar 10–17 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | Sep 12–26 (sowing) |
| Summer squash / zucchini | Mar 10–17 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | Sep 12–26 (sowing) |
| Winter squash | Mar 10–17 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | – |
| Pumpkin | – | Apr 14–28 (sow outdoors) | – |
| Watermelon | Mar 10–17 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 10–17 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Okra | Feb 24–Mar 10 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | – |
| Celery | Jan 13–27 | Apr 14–21 (transplant) | – |
| Basil | Feb 24–Mar 10 | Apr 14–28 (transplant) Apr 14–28 (sow outdoors) | – |
| Cilantro | – | Mar 24–Apr 21 (sow outdoors) | Oct 10–24 (sowing) |
| Parsley | Jan 27–Feb 10 | Mar 24–Apr 7 (transplant) Mar 17–Apr 7 (sow outdoors) | – |
| Dill | – | Apr 7–21 (sow outdoors) | Oct 10–24 (sowing) |
| Sunflower | – | Apr 7–21 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 10–24 (transplant) | – |
| Rhubarb (crowns) | – | Mar 10–24 (transplant) | – |
| Strawberry (plants) | – | Mar 10–24 (transplant) | Sep 26–Oct 24 (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: Angwin Pacific Union College, CA (NOAA GHCN-Daily ID USC00040212), elevation 1,715 ft, 2.4 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Saint Helena, CA | 4 mi | Feb 3 | Dec 4 |
| Calistoga, CA | 11 mi | Mar 2 | Nov 23 |
| Markley Cove, CA | 16 mi | Mar 6 | Nov 30 |
The average last-frost dates of these stations span 66 days, a rough guide to local variation. See data sources & methods.
Frost questions for 94574
When is the last frost in 94574?
The average (50% chance) last spring freeze of 32°F for ZIP 94574 is April 7. For a more cautious planting date, use April 30, when only 1 year in 10 still sees a later freeze.
When is the first frost in 94574?
The average first fall freeze is December 5. In 1 year in 10 it comes by November 14.
What hardiness zone is 94574?
ZIP 94574 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 94574 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
94576 Deer Park 94508 Angwin 94573 Rutherford 94562 Oakville 94567 95452 Kenwood 94599 Yountville 95409 Santa Rosa
Other ZIP codes in Napa County
94503 94508 94558 94559 94562 94567 94573 94576 94599 All Napa 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.