Frost dates for 56001Mankato, MN
The average last spring frost in Mankato is April 30 and the average first fall frost is October 9, giving a typical growing season of about 161 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 30
- Average first fall frost
- Oct 9
- Growing season
- 161 days
Safer after May 12 (1-in-10 risk)
Possible by Sep 25 (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) | Apr 26 · May 8 · May 23 | Sep 17 · Sep 30 · Oct 12 | 143 days | 100% |
| Frost / freeze (32°F) | Apr 16 · Apr 30 · May 12 | Sep 25 · Oct 9 · Oct 22 | 161 days | 100% |
| Hard freeze (28°F) | Apr 6 · Apr 19 · May 2 | Oct 4 · Oct 20 · Nov 1 | 182 days | 100% |
Planting calendar for Mankato
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 | Mar 30 – Jun 5 |
| Tomatoes | Transplant outdoors | May 16 – Jun 19 |
| Peppers | Start seeds indoors | Mar 30 – Apr 30 |
| Peppers | Transplant outdoors | May 30 – Jun 30 |
| Eggplant | Start seeds indoors | Apr 16 – May 15 |
| Eggplant | Transplant outdoors | May 30 – Jun 30 |
| Cucumbers | Sow outdoors | May 30 – Jun 29 |
| Summer squash | Sow outdoors | May 16 – Jun 30 |
| Winter squash & pumpkins | Sow outdoors | May 30 – Jun 30 |
| Snap beans | Sow outdoors | May 16 – Jul 22 |
| Sweet corn | Sow outdoors | May 16 – Jun 19 |
| Watermelon & cantaloupe | Sow outdoors | May 30 – Jun 30 |
| Okra | Sow outdoors | May 23 – Jun 15 |
| Peas | Sow outdoors (spring) | Mar 30 – May 15 |
| Potatoes | Plant outdoors (spring) | Mar 30 – May 30 |
| Onions | Start seeds indoors (spring) | Feb 16 – Mar 15 |
| Onions | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (spring) | Mar 12 – Apr 15 |
| Broccoli | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (fall) | Jun 9 – Jun 19 |
| Broccoli | Transplant outdoors (fall) | Jul 9 – Jul 20 |
| Cabbage | Start seeds indoors (spring) | Mar 2 – Mar 30 |
| Cabbage | Transplant outdoors (spring) | Mar 30 – Apr 30 |
| Cabbage | Start seeds indoors (fall) | May 30 – Jun 29 |
| Cabbage | Transplant outdoors (fall) | Jun 29 – Jul 30 |
| Leaf lettuce | Sow outdoors (spring) | Mar 30 – Jun 15 |
| Leaf lettuce | Sow outdoors (fall) | Jun 29 – Aug 15 |
| Spinach | Sow outdoors (spring) | Mar 23 – May 6 |
| Spinach | Sow outdoors (fall) | Jul 16 – Aug 20 |
| Radishes | Sow outdoors (spring) | Mar 30 – May 20 |
| Radishes | Sow outdoors (fall) | Jun 29 – Aug 30 |
| Kale | Sow outdoors (spring) | Apr 16 – May 6 |
| Kale | Sow outdoors (fall) | Jun 22 – Jul 30 |
| Carrots | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Carrots | Sow outdoors (fall) | May 30 – Jul 15 |
| Garlic | Plant outdoors (fall) | Sep 29 – Oct 30 |
Where these dates come from
ZIP code 56001 is matched to the NOAA station Mankato, MN, 2 km away, at 850 ft elevation (141 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mankato, MN (used) | 850 ft | Apr 30 | Oct 9 |
| St Peter, MN | 795 ft | May 2 | Oct 4 |
| Amboy, MN | 1,030 ft | Apr 30 | Oct 7 |
| New Ulm 3Se, MN | 925 ft | May 2 | Oct 7 |
Frost dates near Mankato
- Mankato, MN 56002 · last Apr 30, first Oct 9
- Eagle Lake, MN 56024 · last Apr 30, first Oct 9
- Saint Clair, MN 56080 · last Apr 30, first Oct 9
- Kasota, MN 56050 · last May 2, first Oct 4
- Madison Lake, MN 56063 · last Apr 30, first Oct 9
- Lake Crystal, MN 56055 · last Apr 30, first Oct 9
- Good Thunder, MN 56037 · last Apr 30, first Oct 7
- Garden City, MN 56034 · last Apr 30, first Oct 7
Frequently asked questions
- When is the last frost in Mankato, MN?
- For ZIP code 56001, the average last spring frost (32°F) is April 30, based on NOAA 1991-2020 climate normals for the Mankato, MN weather station. There is a 1-in-10 chance of a frost after May 12.
- When is the first frost in Mankato, MN?
- The average first fall frost (32°F) is October 9. There is a 1-in-10 chance of frost by September 25, so tender plants are at risk from that point on.
- How long is the growing season in 56001?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 161 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.