Fall in zone 6aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 48817 (Corunna, MI)
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, Corunna 2 NE, MI (2 miles away).
- Average last spring frostMay 550% chance of a 32°F freeze after this date
- Average first fall frostOct 1450% chance of a 32°F freeze by this date
- Growing season (frost-free)160 daysmedian, 32°F threshold
- USDA hardiness zone6a-10 to -5°F avg. coldest night
Get The Dial for 48817 (Corunna)
Frost and freeze alerts from the NWS forecast for 48817, 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 48817 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 mid-April to early May.
Fertilizer window
Lawn region: North (cool-season). Timing only; always follow the product label.
- Kentucky bluegrass (cool-season): Early fall: Around Labor Day (late August–September); Late fall: Late October–November, before the ground freezes; Late spring: Optional around Memorial Day. Avoid: Early-spring and midsummer feeding (pushes top growth, favors crabgrass).
Plant now
No vegetable planting windows are open this week.
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) | Apr 20 |
| 50% (the "average" last frost) | May 5 |
| 10% (cautious: only 1 year in 10 freezes later) | May 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) | Sep 29 |
| 50% (the "average" first frost) | Oct 14 |
| 90% (late: most years have frozen by now) | Oct 29 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 17 | Oct 1 |
| 32°F (freeze) | May 5 | Oct 14 |
| 28°F (hard freeze) | Apr 24 | Oct 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 48817
Dates count from your average last spring frost (May 5) and first fall frost (Oct 14). 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 | Mar 10–24 | May 12–26 (transplant) | – |
| Pepper (sweet and hot) | Feb 24–Mar 10 | May 19–Jun 2 (transplant) | – |
| Eggplant | Feb 24–Mar 10 | May 19–Jun 2 (transplant) | – |
| Tomatillo | Mar 10–24 | May 12–26 (transplant) | – |
| Lettuce | Mar 10–24 | Apr 14–May 5 (transplant) Apr 7–May 19 (sow outdoors) | Aug 19–Sep 9 (transplant) Aug 5–Sep 2 (sowing) |
| Spinach | – | Mar 24–Apr 14 (sow outdoors) | Aug 19–Sep 9 (sowing) |
| Kale | Mar 10–24 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | Jul 22–Aug 19 (transplant) Jul 8–Aug 5 (sowing) |
| Collards | Mar 10–24 | Apr 7–May 5 (transplant) Apr 7–May 5 (sow outdoors) | Jul 22–Aug 19 (transplant) Jul 8–Aug 5 (sowing) |
| Broccoli | Feb 24–Mar 10 | Apr 7–21 (transplant) | Jul 8–Aug 5 (transplant) |
| Cabbage | Feb 24–Mar 10 | Apr 7–21 (transplant) | Jul 8–Aug 5 (transplant) |
| Cauliflower | Feb 24–Mar 10 | Apr 21–May 5 (transplant) | Jul 8–Aug 5 (transplant) |
| Brussels sprouts | Feb 10–24 | Apr 7–21 (transplant) | Jun 24–Jul 15 (transplant) |
| Kohlrabi | Mar 10–24 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | Aug 5–19 (sowing) |
| Bok choy / Asian greens | – | Apr 7–21 (sow outdoors) | Aug 19–Sep 2 (sowing) |
| Arugula | – | Apr 7–May 5 (sow outdoors) | Aug 19–Sep 16 (sowing) |
| Mustard greens | – | Apr 7–28 (sow outdoors) | Aug 19–Sep 2 (sowing) |
| Swiss chard | Mar 24–Apr 7 | Apr 21–May 12 (transplant) Apr 21–May 19 (sow outdoors) | Aug 5–19 (sowing) |
| Beet | – | Apr 7–May 5 (sow outdoors) | Aug 5–19 (sowing) |
| Carrot | – | Apr 14–May 12 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Radish | – | Mar 31–May 12 (sow outdoors) | Sep 2–16 (sowing) |
| Turnip | – | Apr 7–28 (sow outdoors) | Aug 5–19 (sowing) |
| Parsnip | – | Apr 14–May 5 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 10–Apr 7 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Onion (bulbing) | Feb 10–24 | Mar 24–Apr 7 (transplant) | – |
| Green onion / scallion | – | Mar 24–Apr 21 (sow outdoors) | Aug 5–19 (sowing) |
| Leek | Feb 10–24 | Apr 7–21 (transplant) | – |
| Garlic | – | – | Sep 2–30 (sowing) |
| Shallot | – | Mar 24–Apr 7 (transplant) | Sep 2–30 (sowing) |
| Potato | – | Apr 7–21 (transplant) | Jun 24–Jul 8 (transplant) |
| Sweet potato | – | May 26–Jun 9 (transplant) | – |
| Sweet corn | – | May 12–26 (sow outdoors) | – |
| Bean, bush (snap) | – | May 12–26 (sow outdoors) | – |
| Bean, pole | – | May 12–26 (sow outdoors) | – |
| Lima bean | – | May 19–Jun 2 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 26–Jun 16 (sow outdoors) | – |
| Cucumber | Apr 7–14 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Summer squash / zucchini | Apr 7–14 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Winter squash | Apr 7–14 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Pumpkin | – | May 12–26 (sow outdoors) | – |
| Watermelon | Apr 7–14 | May 19–Jun 2 (transplant) May 19–Jun 2 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 7–14 | May 19–Jun 2 (transplant) May 19–Jun 2 (sow outdoors) | – |
| Okra | Mar 24–Apr 7 | May 19–Jun 2 (transplant) May 19–Jun 2 (sow outdoors) | – |
| Celery | Feb 10–24 | May 12–19 (transplant) | – |
| Basil | Mar 24–Apr 7 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Cilantro | – | Apr 21–May 19 (sow outdoors) | Aug 19–Sep 2 (sowing) |
| Parsley | Feb 24–Mar 10 | Apr 21–May 5 (transplant) Apr 14–May 5 (sow outdoors) | – |
| Dill | – | May 5–19 (sow outdoors) | Aug 19–Sep 2 (sowing) |
| Sunflower | – | May 5–19 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 7–21 (transplant) | – |
| Rhubarb (crowns) | – | Apr 7–21 (transplant) | – |
| Strawberry (plants) | – | Apr 7–21 (transplant) | Aug 5–Sep 2 (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: Corunna 2 NE, MI (NOAA GHCN-Daily ID USC00201818), elevation 762 ft, 1.9 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Durand Wwtp, MI | 7 mi | May 3 | Oct 11 |
| Owosso Wwtp, MI | 7 mi | May 1 | Oct 15 |
| Flint 7W, MI | 14 mi | May 3 | Oct 13 |
The average last-frost dates of these stations span 4 days, a rough guide to local variation. See data sources & methods.
Frost questions for 48817
When is the last frost in 48817?
The average (50% chance) last spring freeze of 32°F for ZIP 48817 is May 5. For a more cautious planting date, use May 20, when only 1 year in 10 still sees a later freeze.
When is the first frost in 48817?
The average first fall freeze is October 14. In 1 year in 10 it comes by September 29.
What hardiness zone is 48817?
ZIP 48817 is in USDA zone 6a (-10 to -5°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 48817 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
48449 Lennon 48476 Vernon 48867 Owosso 48429 Durand 48460 New Lothrop 48433 Flushing 48414 Bancroft 48841 Henderson
Other ZIP codes in Shiawassee County
48414 48418 48429 48449 48460 48476 48841 48848 48857 48867 48872 All Shiawassee County frost dates · Michigan 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.