Frost dates for 66506Manhattan, KS
The average last spring frost in Manhattan is April 16 and the average first fall frost is October 19, giving a typical growing season of about 185 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 16
- Average first fall frost
- Oct 19
- Growing season
- 185 days
Safer after May 1 (1-in-10 risk)
Possible by Oct 1 (1-in-10 risk)
Last frost typically in 164 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 13 · Apr 27 · May 11 | Sep 25 · Oct 9 · Oct 22 | 165 days | 100% |
| Frost / freeze (32°F) | Apr 1 · Apr 16 · May 1 | Oct 1 · Oct 19 · Nov 1 | 185 days | 100% |
| Hard freeze (28°F) | Mar 22 · Apr 6 · Apr 24 | Oct 11 · Oct 29 · Nov 12 | 204 days | 100% |
Planting calendar for Manhattan
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 16 – May 22 |
| Tomatoes | Transplant outdoors | May 2 – Jun 29 |
| Peppers | Start seeds indoors | Mar 16 – Apr 16 |
| Peppers | Transplant outdoors | May 16 – Jun 16 |
| Eggplant | Start seeds indoors | Apr 2 – May 1 |
| Eggplant | Transplant outdoors | May 16 – Jun 16 |
| Cucumbers | Sow outdoors | May 16 – Jul 9 |
| Summer squash | Sow outdoors | May 2 – Jun 16 |
| Winter squash & pumpkins | Sow outdoors | May 16 – Jun 16 |
| Snap beans | Sow outdoors | May 2 – Aug 1 |
| Sweet corn | Sow outdoors | May 2 – Jun 29 |
| Watermelon & cantaloupe | Sow outdoors | May 16 – Jun 16 |
| Okra | Sow outdoors | May 9 – Jun 1 |
| Peas | Sow outdoors (spring) | Mar 16 – May 1 |
| Potatoes | Plant outdoors (spring) | Mar 16 – May 16 |
| Onions | Start seeds indoors (spring) | Feb 2 – Mar 1 |
| Onions | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (spring) | Feb 26 – Apr 1 |
| Broccoli | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (fall) | Jun 19 – Jun 29 |
| Broccoli | Transplant outdoors (fall) | Jul 19 – Jul 30 |
| Cabbage | Start seeds indoors (spring) | Feb 16 – Mar 16 |
| Cabbage | Transplant outdoors (spring) | Mar 16 – Apr 16 |
| Cabbage | Start seeds indoors (fall) | Jun 9 – Jul 9 |
| Cabbage | Transplant outdoors (fall) | Jul 9 – Aug 9 |
| Leaf lettuce | Sow outdoors (spring) | Mar 16 – Jun 1 |
| Leaf lettuce | Sow outdoors (fall) | Jul 9 – Aug 25 |
| Spinach | Sow outdoors (spring) | Mar 9 – Apr 22 |
| Spinach | Sow outdoors (fall) | Jul 26 – Aug 30 |
| Radishes | Sow outdoors (spring) | Mar 16 – May 6 |
| Radishes | Sow outdoors (fall) | Jul 9 – Sep 9 |
| Kale | Sow outdoors (spring) | Apr 2 – Apr 22 |
| Kale | Sow outdoors (fall) | Jul 2 – Aug 9 |
| Carrots | Sow outdoors (spring) | Apr 16 – Jun 1 |
| Carrots | Sow outdoors (fall) | Jun 9 – Jul 25 |
| Garlic | Plant outdoors (fall) | Oct 9 – Nov 9 |
Where these dates come from
ZIP code 66506 is matched to the NOAA station Manhattan, KS, 0.3 km away, at 1,060 ft elevation (6 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Manhattan, KS (used) | 1,060 ft | Apr 16 | Oct 19 |
| Tuttle Creek Lake, KS | 1,058 ft | Apr 22 | Oct 20 |
| Manhattan Muni Ap, KS | 1,057 ft | Apr 21 | Oct 16 |
| Manhattan 6 Ssw, KS | 1,137 ft | Apr 19 | Oct 17 |
Frost dates near Manhattan
- Manhattan, KS 66502 · last Apr 16, first Oct 19
- Saint George, KS 66535 · last Apr 18, first Oct 19
- Ogden, KS 66517 · last Apr 21, first Oct 16
- Fort Riley, KS 66442 · last Apr 12, first Oct 26
- Wamego, KS 66547 · last Apr 18, first Oct 19
- Riley, KS 66531 · last Apr 12, first Oct 26
- Olsburg, KS 66520 · last Apr 22, first Oct 20
- Westmoreland, KS 66549 · last Apr 18, first Oct 19
Frequently asked questions
- When is the last frost in Manhattan, KS?
- For ZIP code 66506, the average last spring frost (32°F) is April 16, based on NOAA 1991-2020 climate normals for the Manhattan, KS weather station. There is a 1-in-10 chance of a frost after May 1.
- When is the first frost in Manhattan, KS?
- The average first fall frost (32°F) is October 19. There is a 1-in-10 chance of frost by October 1, so tender plants are at risk from that point on.
- How long is the growing season in 66506?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 185 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.