Frost dates for 51023Hawarden, IA
The average last spring frost in Hawarden is May 1 and the average first fall frost is October 4, giving a typical growing season of about 155 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 1
- Average first fall frost
- Oct 4
- Growing season
- 155 days
Safer after May 14 (1-in-10 risk)
Possible by Sep 21 (1-in-10 risk)
Last frost typically in 186 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 27 · May 8 · May 24 | Sep 14 · Sep 26 · Oct 9 | 139 days | 100% |
| Frost / freeze (32°F) | Apr 17 · May 1 · May 14 | Sep 21 · Oct 4 · Oct 18 | 155 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 22 · May 4 | Sep 30 · Oct 16 · Oct 29 | 174 days | 100% |
Planting calendar for Hawarden
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 31 – Jun 6 |
| Tomatoes | Transplant outdoors | May 17 – Jun 14 |
| Peppers | Start seeds indoors | Mar 31 – May 1 |
| Peppers | Transplant outdoors | May 31 – Jul 1 |
| Eggplant | Start seeds indoors | Apr 17 – May 16 |
| Eggplant | Transplant outdoors | May 31 – Jul 1 |
| Cucumbers | Sow outdoors | May 31 – Jun 24 |
| Summer squash | Sow outdoors | May 17 – Jul 1 |
| Winter squash & pumpkins | Sow outdoors | May 31 – Jul 1 |
| Snap beans | Sow outdoors | May 17 – Jul 17 |
| Sweet corn | Sow outdoors | May 17 – Jun 14 |
| Watermelon & cantaloupe | Sow outdoors | May 31 – Jul 1 |
| Okra | Sow outdoors | May 24 – Jun 16 |
| Peas | Sow outdoors (spring) | Mar 31 – May 16 |
| Potatoes | Plant outdoors (spring) | Mar 31 – May 31 |
| Onions | Start seeds indoors (spring) | Feb 17 – Mar 16 |
| Onions | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (spring) | Mar 13 – Apr 16 |
| Broccoli | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (fall) | Jun 4 – Jun 14 |
| Broccoli | Transplant outdoors (fall) | Jul 4 – Jul 15 |
| Cabbage | Start seeds indoors (spring) | Mar 3 – Mar 31 |
| Cabbage | Transplant outdoors (spring) | Mar 31 – May 1 |
| Cabbage | Start seeds indoors (fall) | May 25 – Jun 24 |
| Cabbage | Transplant outdoors (fall) | Jun 24 – Jul 25 |
| Leaf lettuce | Sow outdoors (spring) | Mar 31 – Jun 16 |
| Leaf lettuce | Sow outdoors (fall) | Jun 24 – Aug 10 |
| Spinach | Sow outdoors (spring) | Mar 24 – May 7 |
| Spinach | Sow outdoors (fall) | Jul 11 – Aug 15 |
| Radishes | Sow outdoors (spring) | Mar 31 – May 21 |
| Radishes | Sow outdoors (fall) | Jun 24 – Aug 25 |
| Kale | Sow outdoors (spring) | Apr 17 – May 7 |
| Kale | Sow outdoors (fall) | Jun 17 – Jul 25 |
| Carrots | Sow outdoors (spring) | May 1 – Jun 16 |
| Carrots | Sow outdoors (fall) | May 25 – Jul 10 |
| Garlic | Plant outdoors (fall) | Sep 24 – Oct 25 |
Where these dates come from
ZIP code 51023 is matched to the NOAA station Hawarden, IA, 1 km away, at 1,190 ft elevation (31 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hawarden, IA (used) | 1,190 ft | May 1 | Oct 4 |
| Sioux Ctr 2 Se, IA | 1,360 ft | Apr 30 | Oct 3 |
| Centerville 6 Se, SD | 1,276 ft | May 2 | Oct 1 |
| Canton, SD | 1,316 ft | May 2 | Oct 2 |
Frost dates near Hawarden
- Chatsworth, IA 51011 · last May 1, first Oct 4
- Ireton, IA 51027 · last Apr 30, first Oct 3
- Alcester, SD 57001 · last May 1, first Oct 4
- Hudson, SD 57034 · last May 1, first Oct 4
- Akron, IA 51001 · last May 1, first Oct 4
- Fairview, SD 57027 · last May 2, first Oct 2
- Maurice, IA 51036 · last Apr 30, first Oct 3
- Sioux Center, IA 51250 · last Apr 30, first Oct 3
Frequently asked questions
- When is the last frost in Hawarden, IA?
- For ZIP code 51023, the average last spring frost (32°F) is May 1, based on NOAA 1991-2020 climate normals for the Hawarden, IA weather station. There is a 1-in-10 chance of a frost after May 14.
- When is the first frost in Hawarden, IA?
- The average first fall frost (32°F) is October 4. There is a 1-in-10 chance of frost by September 21, so tender plants are at risk from that point on.
- How long is the growing season in 51023?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 155 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.