Fall in zone 5aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 49820 (Mackinac County, 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, Engadine Mdot, MI (6 miles away).
- Average last spring frostMay 2650% chance of a 32°F freeze after this date
- Average first fall frostSep 3050% chance of a 32°F freeze by this date
- Growing season (frost-free)127 daysmedian, 32°F threshold
- USDA hardiness zone5a-20 to -15°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
47°F Below 50°F
24-hour average · latest 47°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Chatham 1 SE (61 mi).
4-inch depth
48°F Below 50°F
24-hour average · latest 48°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Chatham 1 SE (61 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 49820 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 48°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically 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) | May 12 |
| 50% (the "average" last frost) | May 26 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 10 |
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 13 |
| 50% (the "average" first frost) | Sep 30 |
| 90% (late: most years have frozen by now) | Oct 13 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Jun 7 | Sep 15 |
| 32°F (freeze) | May 26 | Sep 30 |
| 28°F (hard freeze) | May 11 | Oct 12 |
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 49820
Dates count from your average last spring frost (May 26) and first fall frost (Sep 30). 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 31–Apr 14 | Jun 2–16 (transplant) | – |
| Pepper (sweet and hot) | Mar 17–31 | Jun 9–23 (transplant) | – |
| Eggplant | Mar 17–31 | Jun 9–23 (transplant) | – |
| Tomatillo | Mar 31–Apr 14 | Jun 2–16 (transplant) | – |
| Lettuce | Mar 31–Apr 14 | May 5–26 (transplant) Apr 28–Jun 9 (sow outdoors) | Aug 5–26 (transplant) Jul 22–Aug 19 (sowing) |
| Spinach | – | Apr 14–May 5 (sow outdoors) | Aug 5–26 (sowing) |
| Kale | Mar 31–Apr 14 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | Jul 8–Aug 5 (transplant) Jun 24–Jul 22 (sowing) |
| Collards | Mar 31–Apr 14 | Apr 28–May 26 (transplant) Apr 28–May 26 (sow outdoors) | Jul 8–Aug 5 (transplant) Jun 24–Jul 22 (sowing) |
| Broccoli | Mar 17–31 | Apr 28–May 12 (transplant) | Jun 24–Jul 22 (transplant) |
| Cabbage | Mar 17–31 | Apr 28–May 12 (transplant) | Jun 24–Jul 22 (transplant) |
| Cauliflower | Mar 17–31 | May 12–26 (transplant) | Jun 24–Jul 22 (transplant) |
| Brussels sprouts | Mar 3–17 | Apr 28–May 12 (transplant) | Jun 10–Jul 1 (transplant) |
| Kohlrabi | Mar 31–Apr 14 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Bok choy / Asian greens | – | Apr 28–May 12 (sow outdoors) | Aug 5–19 (sowing) |
| Arugula | – | Apr 28–May 26 (sow outdoors) | Aug 5–Sep 2 (sowing) |
| Mustard greens | – | Apr 28–May 19 (sow outdoors) | Aug 5–19 (sowing) |
| Swiss chard | Apr 14–28 | May 12–Jun 2 (transplant) May 12–Jun 9 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Beet | – | Apr 28–May 26 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Carrot | – | May 5–Jun 2 (sow outdoors) | Jul 8–22 (sowing) |
| Radish | – | Apr 21–Jun 2 (sow outdoors) | Aug 19–Sep 2 (sowing) |
| Turnip | – | Apr 28–May 19 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Parsnip | – | May 5–26 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 31–Apr 28 (sow outdoors) | Jul 8–22 (sowing) |
| Onion (bulbing) | Mar 3–17 | Apr 14–28 (transplant) | – |
| Green onion / scallion | – | Apr 14–May 12 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Leek | Mar 3–17 | Apr 28–May 12 (transplant) | – |
| Garlic | – | – | Aug 19–Sep 16 (sowing) |
| Shallot | – | Apr 14–28 (transplant) | Aug 19–Sep 16 (sowing) |
| Potato | – | Apr 28–May 12 (transplant) | Jun 10–24 (transplant) |
| Sweet potato | – | Jun 16–30 (transplant) | – |
| Sweet corn | – | Jun 2–16 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 2–16 (sow outdoors) | – |
| Bean, pole | – | Jun 2–16 (sow outdoors) | – |
| Lima bean | – | Jun 9–23 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 16–Jul 7 (sow outdoors) | – |
| Cucumber | Apr 28–May 5 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Summer squash / zucchini | Apr 28–May 5 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Winter squash | Apr 28–May 5 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Pumpkin | – | Jun 2–16 (sow outdoors) | – |
| Watermelon | Apr 28–May 5 | Jun 9–23 (transplant) Jun 9–23 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 28–May 5 | Jun 9–23 (transplant) Jun 9–23 (sow outdoors) | – |
| Okra | Apr 14–28 | Jun 9–23 (transplant) Jun 9–23 (sow outdoors) | – |
| Celery | Mar 3–17 | Jun 2–9 (transplant) | – |
| Basil | Apr 14–28 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Cilantro | – | May 12–Jun 9 (sow outdoors) | Aug 5–19 (sowing) |
| Parsley | Mar 17–31 | May 12–26 (transplant) May 5–26 (sow outdoors) | – |
| Dill | – | May 26–Jun 9 (sow outdoors) | Aug 5–19 (sowing) |
| Sunflower | – | May 26–Jun 9 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 28–May 12 (transplant) | – |
| Rhubarb (crowns) | – | Apr 28–May 12 (transplant) | – |
| Strawberry (plants) | – | Apr 28–May 12 (transplant) | Jul 22–Aug 19 (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: Engadine Mdot, MI (NOAA GHCN-Daily ID USC00202598), elevation 685 ft, 5.9 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Newberry Correctional Facility, MI | 12 mi | May 21 | Oct 5 |
| Trout Lake 1SW, MI | 30 mi | May 21 | Oct 1 |
| Manistique Wwtp, MI | 33 mi | May 9 | Oct 10 |
The average last-frost dates of these stations span 17 days, a rough guide to local variation. See data sources & methods.
Frost questions for 49820
When is the last frost in 49820?
The average (50% chance) last spring freeze of 32°F for ZIP 49820 is May 26. For a more cautious planting date, use June 10, when only 1 year in 10 still sees a later freeze.
When is the first frost in 49820?
The average first fall freeze is September 30. In 1 year in 10 it comes by September 13.
What hardiness zone is 49820?
ZIP 49820 is in USDA zone 5a (-20 to -15°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 49820 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
49827 49838 49836 49853 49762 Naubinway 49840 49883 49868 Newberry
Other ZIP codes in Mackinac County
49719 49745 49757 49760 49762 49775 49781 49827 49838 All Mackinac County frost dates · Michigan 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.