Frost dates for 50143Leighton, IA
The average last spring frost in Leighton is April 21 and the average first fall frost is October 16, giving a typical growing season of about 176 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 21
- Average first fall frost
- Oct 16
- Growing season
- 176 days
Safer after May 4 (1-in-10 risk)
Possible by Sep 29 (1-in-10 risk)
Last frost typically in 170 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 18 · May 1 · May 14 | Sep 21 · Oct 4 · Oct 19 | 156 days | 100% |
| Frost / freeze (32°F) | Apr 8 · Apr 21 · May 4 | Sep 29 · Oct 16 · Oct 29 | 176 days | 100% |
| Hard freeze (28°F) | Mar 29 · Apr 11 · Apr 26 | Oct 10 · Oct 27 · Nov 8 | 198 days | 100% |
Planting calendar for Leighton
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 21 – May 27 |
| Tomatoes | Transplant outdoors | May 7 – Jun 26 |
| Peppers | Start seeds indoors | Mar 21 – Apr 21 |
| Peppers | Transplant outdoors | May 21 – Jun 21 |
| Eggplant | Start seeds indoors | Apr 7 – May 6 |
| Eggplant | Transplant outdoors | May 21 – Jun 21 |
| Cucumbers | Sow outdoors | May 21 – Jul 6 |
| Summer squash | Sow outdoors | May 7 – Jun 21 |
| Winter squash & pumpkins | Sow outdoors | May 21 – Jun 21 |
| Snap beans | Sow outdoors | May 7 – Jul 29 |
| Sweet corn | Sow outdoors | May 7 – Jun 26 |
| Watermelon & cantaloupe | Sow outdoors | May 21 – Jun 21 |
| Okra | Sow outdoors | May 14 – Jun 6 |
| Peas | Sow outdoors (spring) | Mar 21 – May 6 |
| Potatoes | Plant outdoors (spring) | Mar 21 – May 21 |
| Onions | Start seeds indoors (spring) | Feb 7 – Mar 6 |
| Onions | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (spring) | Mar 3 – Apr 6 |
| Broccoli | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (fall) | Jun 16 – Jun 26 |
| Broccoli | Transplant outdoors (fall) | Jul 16 – Jul 27 |
| Cabbage | Start seeds indoors (spring) | Feb 21 – Mar 21 |
| Cabbage | Transplant outdoors (spring) | Mar 21 – Apr 21 |
| Cabbage | Start seeds indoors (fall) | Jun 6 – Jul 6 |
| Cabbage | Transplant outdoors (fall) | Jul 6 – Aug 6 |
| Leaf lettuce | Sow outdoors (spring) | Mar 21 – Jun 6 |
| Leaf lettuce | Sow outdoors (fall) | Jul 6 – Aug 22 |
| Spinach | Sow outdoors (spring) | Mar 14 – Apr 27 |
| Spinach | Sow outdoors (fall) | Jul 23 – Aug 27 |
| Radishes | Sow outdoors (spring) | Mar 21 – May 11 |
| Radishes | Sow outdoors (fall) | Jul 6 – Sep 6 |
| Kale | Sow outdoors (spring) | Apr 7 – Apr 27 |
| Kale | Sow outdoors (fall) | Jun 29 – Aug 6 |
| Carrots | Sow outdoors (spring) | Apr 21 – Jun 6 |
| Carrots | Sow outdoors (fall) | Jun 6 – Jul 22 |
| Garlic | Plant outdoors (fall) | Oct 6 – Nov 6 |
Where these dates come from
ZIP code 50143 is matched to the NOAA station Oskaloosa, IA, 14.3 km away, at 830 ft elevation (0 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Oskaloosa, IA (used) | 830 ft | Apr 21 | Oct 16 |
| Knoxville, IA | 895 ft | Apr 20 | Oct 19 |
| Albia 3 Nne, IA | 880 ft | Apr 24 | Oct 16 |
| Grinnell 3 Sw, IA | 905 ft | May 3 | Oct 6 |
Frost dates near Leighton
- Pella, IA 50219 · last Apr 20, first Oct 19
- Tracy, IA 50256 · last Apr 21, first Oct 16
- Harvey, IA 50119 · last Apr 20, first Oct 19
- Beacon, IA 52534 · last Apr 21, first Oct 16
- New Sharon, IA 50207 · last Apr 21, first Oct 16
- Oskaloosa, IA 52577 · last Apr 21, first Oct 16
- University Park, IA 52595 · last Apr 21, first Oct 16
- Bussey, IA 50044 · last Apr 24, first Oct 16
Frequently asked questions
- When is the last frost in Leighton, IA?
- For ZIP code 50143, the average last spring frost (32°F) is April 21, based on NOAA 1991-2020 climate normals for the Oskaloosa, IA weather station. There is a 1-in-10 chance of a frost after May 4.
- When is the first frost in Leighton, IA?
- The average first fall frost (32°F) is October 16. There is a 1-in-10 chance of frost by September 29, so tender plants are at risk from that point on.
- How long is the growing season in 50143?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 176 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.