Frost dates for 66439Horton, KS
The average last spring frost in Horton is April 18 and the average first fall frost is October 17, giving a typical growing season of about 180 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Oct 17
- Growing season
- 180 days
Safer after May 2 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 167 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 14 · Apr 29 · May 11 | Sep 24 · Oct 7 · Oct 19 | 161 days | 100% |
| Frost / freeze (32°F) | Apr 3 · Apr 18 · May 2 | Oct 2 · Oct 17 · Oct 30 | 180 days | 100% |
| Hard freeze (28°F) | Mar 24 · Apr 9 · Apr 23 | Oct 11 · Oct 27 · Nov 8 | 200 days | 100% |
Planting calendar for Horton
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 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jun 27 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 7 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Jul 30 |
| Sweet corn | Sow outdoors | May 4 – Jun 27 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jun 17 – Jun 27 |
| Broccoli | Transplant outdoors (fall) | Jul 17 – Jul 28 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 7 – Jul 7 |
| Cabbage | Transplant outdoors (fall) | Jul 7 – Aug 7 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 7 – Aug 23 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Jul 24 – Aug 28 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 7 – Sep 7 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jun 30 – Aug 7 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 7 – Jul 23 |
| Garlic | Plant outdoors (fall) | Oct 7 – Nov 7 |
Where these dates come from
ZIP code 66439 is matched to the NOAA station Horton, KS, 1.5 km away, at 1,032 ft elevation (73 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Horton, KS (used) | 1,032 ft | Apr 18 | Oct 17 |
| Hiawatha 1 S, KS | 1,061 ft | Apr 14 | Oct 22 |
| Holton, KS | 1,050 ft | Apr 24 | Oct 14 |
| Atchison, KS | 945 ft | Apr 11 | Oct 29 |
Frost dates near Horton
- Everest, KS 66424 · last Apr 18, first Oct 17
- Whiting, KS 66552 · last Apr 18, first Oct 17
- Powhattan, KS 66527 · last Apr 18, first Oct 17
- Hiawatha, KS 66434 · last Apr 18, first Oct 17
- Muscotah, KS 66058 · last Apr 18, first Oct 17
- Robinson, KS 66532 · last Apr 18, first Oct 17
- Netawaka, KS 66516 · last Apr 24, first Oct 14
- Effingham, KS 66023 · last Apr 18, first Oct 17
Frequently asked questions
- When is the last frost in Horton, KS?
- For ZIP code 66439, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Horton, KS weather station. There is a 1-in-10 chance of a frost after May 2.
- When is the first frost in Horton, KS?
- The average first fall frost (32°F) is October 17. There is a 1-in-10 chance of frost by October 2, so tender plants are at risk from that point on.
- How long is the growing season in 66439?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 180 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.