Frost dates for 50950Des Moines, IA
The average last spring frost in Des Moines is April 23 and the average first fall frost is October 15, giving a typical growing season of about 173 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 23
- Average first fall frost
- Oct 15
- Growing season
- 173 days
Safer after May 6 (1-in-10 risk)
Possible by Sep 30 (1-in-10 risk)
Last frost typically in 188 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 19 · May 3 · May 16 | Sep 21 · Oct 4 · Oct 18 | 155 days | 100% |
| Frost / freeze (32°F) | Apr 8 · Apr 23 · May 6 | Sep 30 · Oct 15 · Oct 28 | 173 days | 100% |
| Hard freeze (28°F) | Mar 31 · Apr 13 · Apr 27 | Oct 11 · Oct 25 · Nov 5 | 193 days | 100% |
Planting calendar for Des Moines
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 23 – May 29 |
| Tomatoes | Transplant outdoors | May 9 – Jun 25 |
| Peppers | Start seeds indoors | Mar 23 – Apr 23 |
| Peppers | Transplant outdoors | May 23 – Jun 23 |
| Eggplant | Start seeds indoors | Apr 9 – May 8 |
| Eggplant | Transplant outdoors | May 23 – Jun 23 |
| Cucumbers | Sow outdoors | May 23 – Jul 5 |
| Summer squash | Sow outdoors | May 9 – Jun 23 |
| Winter squash & pumpkins | Sow outdoors | May 23 – Jun 23 |
| Snap beans | Sow outdoors | May 9 – Jul 28 |
| Sweet corn | Sow outdoors | May 9 – Jun 25 |
| Watermelon & cantaloupe | Sow outdoors | May 23 – Jun 23 |
| Okra | Sow outdoors | May 16 – Jun 8 |
| Peas | Sow outdoors (spring) | Mar 23 – May 8 |
| Potatoes | Plant outdoors (spring) | Mar 23 – May 23 |
| Onions | Start seeds indoors (spring) | Feb 9 – Mar 8 |
| Onions | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (spring) | Mar 5 – Apr 8 |
| Broccoli | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (fall) | Jun 15 – Jun 25 |
| Broccoli | Transplant outdoors (fall) | Jul 15 – Jul 26 |
| Cabbage | Start seeds indoors (spring) | Feb 23 – Mar 23 |
| Cabbage | Transplant outdoors (spring) | Mar 23 – Apr 23 |
| Cabbage | Start seeds indoors (fall) | Jun 5 – Jul 5 |
| Cabbage | Transplant outdoors (fall) | Jul 5 – Aug 5 |
| Leaf lettuce | Sow outdoors (spring) | Mar 23 – Jun 8 |
| Leaf lettuce | Sow outdoors (fall) | Jul 5 – Aug 21 |
| Spinach | Sow outdoors (spring) | Mar 16 – Apr 29 |
| Spinach | Sow outdoors (fall) | Jul 22 – Aug 26 |
| Radishes | Sow outdoors (spring) | Mar 23 – May 13 |
| Radishes | Sow outdoors (fall) | Jul 5 – Sep 5 |
| Kale | Sow outdoors (spring) | Apr 9 – Apr 29 |
| Kale | Sow outdoors (fall) | Jun 28 – Aug 5 |
| Carrots | Sow outdoors (spring) | Apr 23 – Jun 8 |
| Carrots | Sow outdoors (fall) | Jun 5 – Jul 21 |
| Garlic | Plant outdoors (fall) | Oct 5 – Nov 5 |
Where these dates come from
ZIP code 50950 is matched to the NOAA station Ankeny, IA, 9.2 km away, at 975 ft elevation (76 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ankeny, IA (used) | 975 ft | Apr 23 | Oct 15 |
| Des Moines Wsfo-Johnston, IA | 959 ft | Apr 19 | Oct 18 |
| Des Moines Intl Ap, IA | 957 ft | Apr 18 | Oct 20 |
| Des Moines 17 E, IA | 921 ft | Apr 21 | Oct 15 |
Frost dates near Des Moines
- Des Moines, IA 50301 · last Apr 23, first Oct 15
- Berwick, IA 50032 · last Apr 23, first Oct 15
- Ankeny, IA 50021 · last Apr 23, first Oct 15
- Altoona, IA 50009 · last Apr 23, first Oct 15
- Bondurant, IA 50035 · last Apr 23, first Oct 15
- Pleasant Hill, IA 50327 · last Apr 18, first Oct 20
- Johnston, IA 50131 · last Apr 19, first Oct 18
- Urbandale, IA 50398 · last Apr 18, first Oct 20
Frequently asked questions
- When is the last frost in Des Moines, IA?
- For ZIP code 50950, the average last spring frost (32°F) is April 23, based on NOAA 1991-2020 climate normals for the Ankeny, IA weather station. There is a 1-in-10 chance of a frost after May 6.
- When is the first frost in Des Moines, IA?
- The average first fall frost (32°F) is October 15. There is a 1-in-10 chance of frost by September 30, so tender plants are at risk from that point on.
- How long is the growing season in 50950?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 173 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.