Frost dates for 50830Afton, IA
The average last spring frost in Afton is April 28 and the average first fall frost is October 11, giving a typical growing season of about 164 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 28
- Average first fall frost
- Oct 11
- Growing season
- 164 days
Safer after May 9 (1-in-10 risk)
Possible by Sep 24 (1-in-10 risk)
Last frost typically in 183 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 23 · May 6 · May 19 | Sep 16 · Oct 1 · Oct 15 | 145 days | 100% |
| Frost / freeze (32°F) | Apr 14 · Apr 28 · May 9 | Sep 24 · Oct 11 · Oct 26 | 164 days | 100% |
| Hard freeze (28°F) | Apr 5 · Apr 17 · May 2 | Oct 5 · Oct 23 · Nov 4 | 185 days | 100% |
Planting calendar for Afton
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 28 – Jun 3 |
| Tomatoes | Transplant outdoors | May 14 – Jun 21 |
| Peppers | Start seeds indoors | Mar 28 – Apr 28 |
| Peppers | Transplant outdoors | May 28 – Jun 28 |
| Eggplant | Start seeds indoors | Apr 14 – May 13 |
| Eggplant | Transplant outdoors | May 28 – Jun 28 |
| Cucumbers | Sow outdoors | May 28 – Jul 1 |
| Summer squash | Sow outdoors | May 14 – Jun 28 |
| Winter squash & pumpkins | Sow outdoors | May 28 – Jun 28 |
| Snap beans | Sow outdoors | May 14 – Jul 24 |
| Sweet corn | Sow outdoors | May 14 – Jun 21 |
| Watermelon & cantaloupe | Sow outdoors | May 28 – Jun 28 |
| Okra | Sow outdoors | May 21 – Jun 13 |
| Peas | Sow outdoors (spring) | Mar 28 – May 13 |
| Potatoes | Plant outdoors (spring) | Mar 28 – May 28 |
| Onions | Start seeds indoors (spring) | Feb 14 – Mar 13 |
| Onions | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (spring) | Mar 10 – Apr 13 |
| Broccoli | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (fall) | Jun 11 – Jun 21 |
| Broccoli | Transplant outdoors (fall) | Jul 11 – Jul 22 |
| Cabbage | Start seeds indoors (spring) | Feb 28 – Mar 28 |
| Cabbage | Transplant outdoors (spring) | Mar 28 – Apr 28 |
| Cabbage | Start seeds indoors (fall) | Jun 1 – Jul 1 |
| Cabbage | Transplant outdoors (fall) | Jul 1 – Aug 1 |
| Leaf lettuce | Sow outdoors (spring) | Mar 28 – Jun 13 |
| Leaf lettuce | Sow outdoors (fall) | Jul 1 – Aug 17 |
| Spinach | Sow outdoors (spring) | Mar 21 – May 4 |
| Spinach | Sow outdoors (fall) | Jul 18 – Aug 22 |
| Radishes | Sow outdoors (spring) | Mar 28 – May 18 |
| Radishes | Sow outdoors (fall) | Jul 1 – Sep 1 |
| Kale | Sow outdoors (spring) | Apr 14 – May 4 |
| Kale | Sow outdoors (fall) | Jun 24 – Aug 1 |
| Carrots | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Carrots | Sow outdoors (fall) | Jun 1 – Jul 17 |
| Garlic | Plant outdoors (fall) | Oct 1 – Nov 1 |
Where these dates come from
ZIP code 50830 is matched to the NOAA station Creston 2 Sw, IA, 16.7 km away, at 1,296 ft elevation (161 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Creston 2 Sw, IA (used) | 1,296 ft | Apr 28 | Oct 11 |
| Beaconsfield, IA | 1,215 ft | Apr 23 | Oct 17 |
| Winterset 1S, IA | 1,100 ft | Apr 30 | Oct 3 |
| Greenfield, IA | 1,316 ft | Apr 25 | Oct 12 |
Frost dates near Afton
- Thayer, IA 50254 · last Apr 23, first Oct 17
- Arispe, IA 50831 · last Apr 23, first Oct 17
- Creston, IA 50801 · last Apr 28, first Oct 11
- Lorimor, IA 50149 · last Apr 30, first Oct 3
- Shannon City, IA 50861 · last Apr 23, first Oct 17
- Macksburg, IA 50155 · last Apr 30, first Oct 3
- Murray, IA 50174 · last Apr 29, first Oct 9
- Tingley, IA 50863 · last Apr 23, first Oct 17
Frequently asked questions
- When is the last frost in Afton, IA?
- For ZIP code 50830, the average last spring frost (32°F) is April 28, based on NOAA 1991-2020 climate normals for the Creston 2 Sw, IA weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Afton, IA?
- The average first fall frost (32°F) is October 11. There is a 1-in-10 chance of frost by September 24, so tender plants are at risk from that point on.
- How long is the growing season in 50830?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 164 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.