Frost dates for 66956Mankato, KS
The average last spring frost in Mankato is April 30 and the average first fall frost is October 8, giving a typical growing season of about 159 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 30
- Average first fall frost
- Oct 8
- Growing season
- 159 days
Safer after May 10 (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 27 · May 7 · May 18 | Sep 18 · Sep 30 · Oct 11 | 145 days | 100% |
| Frost / freeze (32°F) | Apr 17 · Apr 30 · May 10 | Sep 25 · Oct 8 · Oct 20 | 159 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 22 · May 3 | Sep 30 · Oct 17 · Oct 28 | 176 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 18 |
| 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 28 |
| Summer squash | Sow outdoors | May 16 – Jun 30 |
| Winter squash & pumpkins | Sow outdoors | May 30 – Jun 30 |
| Snap beans | Sow outdoors | May 16 – Jul 21 |
| Sweet corn | Sow outdoors | May 16 – Jun 18 |
| 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 8 – Jun 18 |
| Broccoli | Transplant outdoors (fall) | Jul 8 – Jul 19 |
| Cabbage | Start seeds indoors (spring) | Mar 2 – Mar 30 |
| Cabbage | Transplant outdoors (spring) | Mar 30 – Apr 30 |
| Cabbage | Start seeds indoors (fall) | May 29 – Jun 28 |
| Cabbage | Transplant outdoors (fall) | Jun 28 – Jul 29 |
| Leaf lettuce | Sow outdoors (spring) | Mar 30 – Jun 15 |
| Leaf lettuce | Sow outdoors (fall) | Jun 28 – Aug 14 |
| Spinach | Sow outdoors (spring) | Mar 23 – May 6 |
| Spinach | Sow outdoors (fall) | Jul 15 – Aug 19 |
| Radishes | Sow outdoors (spring) | Mar 30 – May 20 |
| Radishes | Sow outdoors (fall) | Jun 28 – Aug 29 |
| Kale | Sow outdoors (spring) | Apr 16 – May 6 |
| Kale | Sow outdoors (fall) | Jun 21 – Jul 29 |
| Carrots | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Carrots | Sow outdoors (fall) | May 29 – Jul 14 |
| Garlic | Plant outdoors (fall) | Sep 28 – Oct 29 |
Where these dates come from
ZIP code 66956 is matched to the NOAA station Burr Oak 1N, KS, 12.9 km away, at 1,651 ft elevation (78 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Burr Oak 1N, KS (used) | 1,651 ft | Apr 30 | Oct 8 |
| Mankato, KS | 1,750 ft | Apr 30 | Oct 14 |
| Lovewell Dam, KS | 1,602 ft | Apr 20 | Oct 19 |
| Courtland, KS | 1,500 ft | Apr 17 | Oct 21 |
Frost dates near Mankato
- Jewell, KS 66949 · last Apr 17, first Oct 21
- Burr Oak, KS 66936 · last Apr 30, first Oct 8
- Formoso, KS 66942 · last Apr 17, first Oct 21
- Esbon, KS 66941 · last Apr 30, first Oct 8
- Randall, KS 66963 · last Apr 17, first Oct 21
- Webber, KS 66970 · last Apr 20, first Oct 19
- Courtland, KS 66939 · last Apr 17, first Oct 21
- Lebanon, KS 66952 · last Apr 24, first Oct 15
Frequently asked questions
- When is the last frost in Mankato, KS?
- For ZIP code 66956, the average last spring frost (32°F) is April 30, based on NOAA 1991-2020 climate normals for the Burr Oak 1N, KS weather station. There is a 1-in-10 chance of a frost after May 10.
- When is the first frost in Mankato, KS?
- The average first fall frost (32°F) is October 8. 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 66956?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 159 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.