Frost dates for 48531Flint, 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 192 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 48531 is matched to the NOAA station Flint Bishop Intl Ap, MI, 6.1 km away, at 770 ft elevation (22 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 48503 · last May 6, first Oct 10
- Burton, MI 48529 · last May 6, first Oct 10
- Grand Blanc, MI 48439 · last May 1, first Oct 14
- Swartz Creek, MI 48473 · last May 6, first Oct 10
- Mount Morris, MI 48458 · last May 3, first Oct 13
- Genesee, MI 48437 · last May 3, first Oct 13
- Davison, MI 48423 · last May 1, first Oct 14
- Atlas, MI 48411 · last May 1, first Oct 14
Frequently asked questions
- When is the last frost in Flint, MI?
- For ZIP code 48531, 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 48531?
- 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.