Frost dates for 48503Flint, MI
The average last spring frost in Flint is May 6 and the average first fall frost is October 10, giving a typical growing season of about 155 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 6
- Average first fall frost
- Oct 10
- Growing season
- 155 days
Safer after May 23 (1-in-10 risk)
Possible by Sep 26 (1-in-10 risk)
Last frost typically in 185 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 2 · May 18 · Jun 2 | Sep 15 · Sep 28 · Oct 10 | 132 days | 100% |
| Frost / freeze (32°F) | Apr 21 · May 6 · May 23 | Sep 26 · Oct 10 · Oct 25 | 155 days | 100% |
| Hard freeze (28°F) | Apr 11 · Apr 26 · May 13 | Oct 6 · Oct 23 · Nov 6 | 179 days | 100% |
Planting calendar for Flint
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 5 – Jun 11 |
| Tomatoes | Transplant outdoors | May 22 – Jun 20 |
| Peppers | Start seeds indoors | Apr 5 – May 6 |
| Peppers | Transplant outdoors | Jun 5 – Jul 6 |
| Eggplant | Start seeds indoors | Apr 22 – May 21 |
| Eggplant | Transplant outdoors | Jun 5 – Jul 6 |
| Cucumbers | Sow outdoors | Jun 5 – Jun 30 |
| Summer squash | Sow outdoors | May 22 – Jul 6 |
| Winter squash & pumpkins | Sow outdoors | Jun 5 – Jul 6 |
| Snap beans | Sow outdoors | May 22 – Jul 23 |
| Sweet corn | Sow outdoors | May 22 – Jun 20 |
| Watermelon & cantaloupe | Sow outdoors | Jun 5 – Jul 6 |
| Okra | Sow outdoors | May 29 – Jun 21 |
| Peas | Sow outdoors (spring) | Apr 5 – May 21 |
| Potatoes | Plant outdoors (spring) | Apr 5 – Jun 5 |
| Onions | Start seeds indoors (spring) | Feb 22 – Mar 21 |
| Onions | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (spring) | Mar 18 – Apr 21 |
| Broccoli | Transplant outdoors (spring) | Apr 22 – May 21 |
| Broccoli | Start seeds indoors (fall) | Jun 10 – Jun 20 |
| Broccoli | Transplant outdoors (fall) | Jul 10 – Jul 21 |
| Cabbage | Start seeds indoors (spring) | Mar 8 – Apr 5 |
| Cabbage | Transplant outdoors (spring) | Apr 5 – May 6 |
| Cabbage | Start seeds indoors (fall) | May 31 – Jun 30 |
| Cabbage | Transplant outdoors (fall) | Jun 30 – Jul 31 |
| Leaf lettuce | Sow outdoors (spring) | Apr 5 – Jun 21 |
| Leaf lettuce | Sow outdoors (fall) | Jun 30 – Aug 16 |
| Spinach | Sow outdoors (spring) | Mar 29 – May 12 |
| Spinach | Sow outdoors (fall) | Jul 17 – Aug 21 |
| Radishes | Sow outdoors (spring) | Apr 5 – May 26 |
| Radishes | Sow outdoors (fall) | Jun 30 – Aug 31 |
| Kale | Sow outdoors (spring) | Apr 22 – May 12 |
| Kale | Sow outdoors (fall) | Jun 23 – Jul 31 |
| Carrots | Sow outdoors (spring) | May 6 – Jun 21 |
| Carrots | Sow outdoors (fall) | May 31 – Jul 16 |
| Garlic | Plant outdoors (fall) | Sep 30 – Oct 31 |
Where these dates come from
ZIP code 48503 is matched to the NOAA station Flint Bishop Intl Ap, MI, 7 km away, at 770 ft elevation (25 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Flint Bishop Intl Ap, MI (used) | 770 ft | May 6 | Oct 10 |
| Flint 7W, MI | 679 ft | May 3 | Oct 13 |
| Burton 4N, MI | 757 ft | May 8 | Oct 5 |
| Goodrich, MI | 910 ft | May 1 | Oct 14 |
Frost dates near Flint
- Flint, MI 48502 · last May 3, first Oct 13
- Burton, MI 48529 · last May 6, first Oct 10
- Grand Blanc, MI 48439 · last May 1, first Oct 14
- Mount Morris, MI 48458 · last May 3, first Oct 13
- Swartz Creek, MI 48473 · last May 6, first Oct 10
- Genesee, MI 48437 · last May 3, first Oct 13
- Davison, MI 48423 · last May 1, first Oct 14
- Flushing, MI 48433 · last May 3, first Oct 13
Frequently asked questions
- When is the last frost in Flint, MI?
- For ZIP code 48503, the average last spring frost (32°F) is May 6, based on NOAA 1991-2020 climate normals for the Flint Bishop Intl Ap, MI weather station. There is a 1-in-10 chance of a frost after May 23.
- When is the first frost in Flint, MI?
- The average first fall frost (32°F) is October 10. There is a 1-in-10 chance of frost by September 26, so tender plants are at risk from that point on.
- How long is the growing season in 48503?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 155 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.