Frost dates for 51648Percival, IA
The average last spring frost in Percival is April 18 and the average first fall frost is October 19, giving a typical growing season of about 182 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Oct 19
- Growing season
- 182 days
Safer after May 1 (1-in-10 risk)
Possible by Oct 3 (1-in-10 risk)
Last frost typically in 173 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 15 · Apr 29 · May 10 | Sep 25 · Oct 8 · Oct 21 | 164 days | 100% |
| Frost / freeze (32°F) | Apr 4 · Apr 18 · May 1 | Oct 3 · Oct 19 · Oct 30 | 182 days | 100% |
| Hard freeze (28°F) | Mar 25 · Apr 9 · Apr 23 | Oct 15 · Oct 28 · Nov 10 | 202 days | 100% |
Planting calendar for Percival
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 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jun 29 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 9 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Aug 1 |
| Sweet corn | Sow outdoors | May 4 – Jun 29 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jun 19 – Jun 29 |
| Broccoli | Transplant outdoors (fall) | Jul 19 – Jul 30 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 9 – Jul 9 |
| Cabbage | Transplant outdoors (fall) | Jul 9 – Aug 9 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 9 – Aug 25 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Jul 26 – Aug 30 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 9 – Sep 9 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jul 2 – Aug 9 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 9 – Jul 25 |
| Garlic | Plant outdoors (fall) | Oct 9 – Nov 9 |
Where these dates come from
ZIP code 51648 is matched to the NOAA station Nebraska City 2Nw, NE, 8 km away, at 1,055 ft elevation (127 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Nebraska City 2Nw, NE (used) | 1,055 ft | Apr 18 | Oct 19 |
| Sidney 1Sse, IA | 1,140 ft | Apr 19 | Oct 19 |
| Glenwood 3Sw, IA | 980 ft | Apr 23 | Oct 11 |
| Weeping Water, NE | 1,100 ft | Apr 23 | Oct 16 |
Frost dates near Percival
- Nebraska City, NE 68410 · last Apr 18, first Oct 19
- Thurman, IA 51654 · last Apr 19, first Oct 19
- Union, NE 68455 · last Apr 18, first Oct 19
- Sidney, IA 51652 · last Apr 19, first Oct 19
- Nehawka, NE 68413 · last Apr 23, first Oct 16
- Dunbar, NE 68346 · last Apr 18, first Oct 19
- Hamburg, IA 51640 · last Apr 19, first Oct 19
- Tabor, IA 51653 · last Apr 19, first Oct 19
Frequently asked questions
- When is the last frost in Percival, IA?
- For ZIP code 51648, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Nebraska City 2Nw, NE weather station. There is a 1-in-10 chance of a frost after May 1.
- When is the first frost in Percival, IA?
- The average first fall frost (32°F) is October 19. There is a 1-in-10 chance of frost by October 3, so tender plants are at risk from that point on.
- How long is the growing season in 51648?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 182 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.