Frost dates for 48748National City, MI
The average last spring frost in National City is May 16 and the average first fall frost is October 5, giving a typical growing season of about 143 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 16
- Average first fall frost
- Oct 5
- Growing season
- 143 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 22 (1-in-10 risk)
Last frost typically in 195 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 12 · May 27 · Jun 7 | Sep 11 · Sep 26 · Oct 7 | 121 days | 100% |
| Frost / freeze (32°F) | May 1 · May 16 · May 30 | Sep 22 · Oct 5 · Oct 19 | 143 days | 100% |
| Hard freeze (28°F) | Apr 22 · May 4 · May 18 | Oct 2 · Oct 18 · Nov 1 | 166 days | 100% |
Planting calendar for National City
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 15 – Jun 21 |
| Tomatoes | Transplant outdoors | Jun 1 – Jun 15 |
| Peppers | Start seeds indoors | Apr 15 – May 16 |
| Peppers | Transplant outdoors | Jun 15 – Jul 16 |
| Eggplant | Start seeds indoors | May 2 – May 31 |
| Eggplant | Transplant outdoors | Jun 15 – Jul 16 |
| Cucumbers | Sow outdoors | Jun 15 – Jun 25 |
| Summer squash | Sow outdoors | Jun 1 – Jul 16 |
| Winter squash & pumpkins | Sow outdoors | Jun 15 – Jul 16 |
| Snap beans | Sow outdoors | Jun 1 – Jul 18 |
| Sweet corn | Sow outdoors | Jun 1 – Jun 15 |
| Watermelon & cantaloupe | Sow outdoors | Jun 15 – Jul 16 |
| Okra | Sow outdoors | Jun 8 – Jul 1 |
| Peas | Sow outdoors (spring) | Apr 15 – May 31 |
| Potatoes | Plant outdoors (spring) | Apr 15 – Jun 15 |
| Onions | Start seeds indoors (spring) | Mar 4 – Mar 31 |
| Onions | Transplant outdoors (spring) | May 2 – May 31 |
| Broccoli | Start seeds indoors (spring) | Mar 28 – May 1 |
| Broccoli | Transplant outdoors (spring) | May 2 – May 31 |
| Broccoli | Start seeds indoors (fall) | Jun 5 – Jun 15 |
| Broccoli | Transplant outdoors (fall) | Jul 5 – Jul 16 |
| Cabbage | Start seeds indoors (spring) | Mar 18 – Apr 15 |
| Cabbage | Transplant outdoors (spring) | Apr 15 – May 16 |
| Cabbage | Start seeds indoors (fall) | May 26 – Jun 25 |
| Cabbage | Transplant outdoors (fall) | Jun 25 – Jul 26 |
| Leaf lettuce | Sow outdoors (spring) | Apr 15 – Jul 1 |
| Leaf lettuce | Sow outdoors (fall) | Jun 25 – Aug 11 |
| Spinach | Sow outdoors (spring) | Apr 8 – May 22 |
| Spinach | Sow outdoors (fall) | Jul 12 – Aug 16 |
| Radishes | Sow outdoors (spring) | Apr 15 – Jun 5 |
| Radishes | Sow outdoors (fall) | Jun 25 – Aug 26 |
| Kale | Sow outdoors (spring) | May 2 – May 22 |
| Kale | Sow outdoors (fall) | Jun 18 – Jul 26 |
| Carrots | Sow outdoors (spring) | May 16 – Jul 1 |
| Carrots | Sow outdoors (fall) | May 26 – Jul 11 |
| Garlic | Plant outdoors (fall) | Sep 25 – Oct 26 |
Where these dates come from
ZIP code 48748 is matched to the NOAA station Hale Loud Dam, MI, 16.9 km away, at 728 ft elevation (56 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hale Loud Dam, MI (used) | 728 ft | May 16 | Oct 5 |
| Hale 5Ssw #2, MI | 816 ft | May 23 | Sep 26 |
| E Tawas, MI | 586 ft | May 8 | Oct 5 |
| Glennie 2Se, MI | 894 ft | May 19 | Sep 29 |
Frost dates near National City
- Tawas City, MI 48763 · last May 8, first Oct 5
- Whittemore, MI 48770 · last May 23, first Sep 26
- Hale, MI 48739 · last May 16, first Oct 5
- East Tawas, MI 48730 · last May 8, first Oct 5
- Long Lake, MI 48743 · last May 21, first Sep 29
- Turner, MI 48765 · last May 5, first Oct 10
- Twining, MI 48766 · last May 5, first Oct 10
- South Branch, MI 48761 · last May 21, first Sep 29
Frequently asked questions
- When is the last frost in National City, MI?
- For ZIP code 48748, the average last spring frost (32°F) is May 16, based on NOAA 1991-2020 climate normals for the Hale Loud Dam, MI weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in National City, MI?
- The average first fall frost (32°F) is October 5. There is a 1-in-10 chance of frost by September 22, so tender plants are at risk from that point on.
- How long is the growing season in 48748?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 143 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.