Frost dates for 50012Ames, IA
The average last spring frost in Ames is April 26 and the average first fall frost is October 8, giving a typical growing season of about 164 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 26
- Average first fall frost
- Oct 8
- Growing season
- 164 days
Safer after May 9 (1-in-10 risk)
Possible by Sep 23 (1-in-10 risk)
Last frost typically in 181 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 21 · May 5 · May 17 | Sep 15 · Sep 28 · Oct 11 | 146 days | 100% |
| Frost / freeze (32°F) | Apr 11 · Apr 26 · May 9 | Sep 23 · Oct 8 · Oct 21 | 164 days | 100% |
| Hard freeze (28°F) | Apr 1 · Apr 14 · May 1 | Oct 4 · Oct 19 · Oct 31 | 184 days | 100% |
Planting calendar for Ames
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 26 – Jun 1 |
| Tomatoes | Transplant outdoors | May 12 – Jun 18 |
| Peppers | Start seeds indoors | Mar 26 – Apr 26 |
| Peppers | Transplant outdoors | May 26 – Jun 26 |
| Eggplant | Start seeds indoors | Apr 12 – May 11 |
| Eggplant | Transplant outdoors | May 26 – Jun 26 |
| Cucumbers | Sow outdoors | May 26 – Jun 28 |
| Summer squash | Sow outdoors | May 12 – Jun 26 |
| Winter squash & pumpkins | Sow outdoors | May 26 – Jun 26 |
| Snap beans | Sow outdoors | May 12 – Jul 21 |
| Sweet corn | Sow outdoors | May 12 – Jun 18 |
| Watermelon & cantaloupe | Sow outdoors | May 26 – Jun 26 |
| Okra | Sow outdoors | May 19 – Jun 11 |
| Peas | Sow outdoors (spring) | Mar 26 – May 11 |
| Potatoes | Plant outdoors (spring) | Mar 26 – May 26 |
| Onions | Start seeds indoors (spring) | Feb 12 – Mar 11 |
| Onions | Transplant outdoors (spring) | Apr 12 – May 11 |
| Broccoli | Start seeds indoors (spring) | Mar 8 – Apr 11 |
| Broccoli | Transplant outdoors (spring) | Apr 12 – May 11 |
| Broccoli | Start seeds indoors (fall) | Jun 8 – Jun 18 |
| Broccoli | Transplant outdoors (fall) | Jul 8 – Jul 19 |
| Cabbage | Start seeds indoors (spring) | Feb 26 – Mar 26 |
| Cabbage | Transplant outdoors (spring) | Mar 26 – Apr 26 |
| Cabbage | Start seeds indoors (fall) | May 29 – Jun 28 |
| Cabbage | Transplant outdoors (fall) | Jun 28 – Jul 29 |
| Leaf lettuce | Sow outdoors (spring) | Mar 26 – Jun 11 |
| Leaf lettuce | Sow outdoors (fall) | Jun 28 – Aug 14 |
| Spinach | Sow outdoors (spring) | Mar 19 – May 2 |
| Spinach | Sow outdoors (fall) | Jul 15 – Aug 19 |
| Radishes | Sow outdoors (spring) | Mar 26 – May 16 |
| Radishes | Sow outdoors (fall) | Jun 28 – Aug 29 |
| Kale | Sow outdoors (spring) | Apr 12 – May 2 |
| Kale | Sow outdoors (fall) | Jun 21 – Jul 29 |
| Carrots | Sow outdoors (spring) | Apr 26 – Jun 11 |
| Carrots | Sow outdoors (fall) | May 29 – Jul 14 |
| Garlic | Plant outdoors (fall) | Sep 28 – Oct 29 |
Where these dates come from
ZIP code 50012 is matched to the NOAA station Ames Muni Ap, IA, 4.1 km away, at 930 ft elevation (11 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ames Muni Ap, IA (used) | 930 ft | Apr 26 | Oct 8 |
| Ames 8 Wsw, IA | 1,099 ft | Apr 23 | Oct 14 |
| Ames 5 Se, IA | 870 ft | Apr 26 | Oct 12 |
| Boone, IA | 1,035 ft | Apr 28 | Oct 12 |
Frost dates near Ames
- Ames, IA 50013 · last Apr 26, first Oct 8
- Kelley, IA 50134 · last Apr 26, first Oct 8
- Gilbert, IA 50105 · last Apr 26, first Oct 8
- Huxley, IA 50124 · last Apr 26, first Oct 12
- Slater, IA 50244 · last Apr 26, first Oct 8
- Cambridge, IA 50046 · last Apr 26, first Oct 12
- Nevada, IA 50201 · last Apr 24, first Oct 12
- Luther, IA 50152 · last Apr 23, first Oct 14
Frequently asked questions
- When is the last frost in Ames, IA?
- For ZIP code 50012, the average last spring frost (32°F) is April 26, based on NOAA 1991-2020 climate normals for the Ames Muni Ap, IA weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Ames, IA?
- The average first fall frost (32°F) is October 8. There is a 1-in-10 chance of frost by September 23, so tender plants are at risk from that point on.
- How long is the growing season in 50012?
- 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.