Frost dates for 52170Waterville, IA
The average last spring frost in Waterville is April 24 and the average first fall frost is October 17, giving a typical growing season of about 175 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 24
- Average first fall frost
- Oct 17
- Growing season
- 175 days
Safer after May 8 (1-in-10 risk)
Possible by Oct 4 (1-in-10 risk)
Last frost typically in 179 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 22 · May 5 · May 19 | Sep 24 · Oct 7 · Oct 20 | 154 days | 100% |
| Frost / freeze (32°F) | Apr 9 · Apr 24 · May 8 | Oct 4 · Oct 17 · Oct 28 | 175 days | 100% |
| Hard freeze (28°F) | Mar 30 · Apr 11 · Apr 29 | Oct 14 · Oct 27 · Nov 7 | 197 days | 100% |
Planting calendar for Waterville
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 24 – May 30 |
| Tomatoes | Transplant outdoors | May 10 – Jun 27 |
| Peppers | Start seeds indoors | Mar 24 – Apr 24 |
| Peppers | Transplant outdoors | May 24 – Jun 24 |
| Eggplant | Start seeds indoors | Apr 10 – May 9 |
| Eggplant | Transplant outdoors | May 24 – Jun 24 |
| Cucumbers | Sow outdoors | May 24 – Jul 7 |
| Summer squash | Sow outdoors | May 10 – Jun 24 |
| Winter squash & pumpkins | Sow outdoors | May 24 – Jun 24 |
| Snap beans | Sow outdoors | May 10 – Jul 30 |
| Sweet corn | Sow outdoors | May 10 – Jun 27 |
| Watermelon & cantaloupe | Sow outdoors | May 24 – Jun 24 |
| Okra | Sow outdoors | May 17 – Jun 9 |
| Peas | Sow outdoors (spring) | Mar 24 – May 9 |
| Potatoes | Plant outdoors (spring) | Mar 24 – May 24 |
| Onions | Start seeds indoors (spring) | Feb 10 – Mar 9 |
| Onions | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (spring) | Mar 6 – Apr 9 |
| Broccoli | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (fall) | Jun 17 – Jun 27 |
| Broccoli | Transplant outdoors (fall) | Jul 17 – Jul 28 |
| Cabbage | Start seeds indoors (spring) | Feb 24 – Mar 24 |
| Cabbage | Transplant outdoors (spring) | Mar 24 – Apr 24 |
| Cabbage | Start seeds indoors (fall) | Jun 7 – Jul 7 |
| Cabbage | Transplant outdoors (fall) | Jul 7 – Aug 7 |
| Leaf lettuce | Sow outdoors (spring) | Mar 24 – Jun 9 |
| Leaf lettuce | Sow outdoors (fall) | Jul 7 – Aug 23 |
| Spinach | Sow outdoors (spring) | Mar 17 – Apr 30 |
| Spinach | Sow outdoors (fall) | Jul 24 – Aug 28 |
| Radishes | Sow outdoors (spring) | Mar 24 – May 14 |
| Radishes | Sow outdoors (fall) | Jul 7 – Sep 7 |
| Kale | Sow outdoors (spring) | Apr 10 – Apr 30 |
| Kale | Sow outdoors (fall) | Jun 30 – Aug 7 |
| Carrots | Sow outdoors (spring) | Apr 24 – Jun 9 |
| Carrots | Sow outdoors (fall) | Jun 7 – Jul 23 |
| Garlic | Plant outdoors (fall) | Oct 7 – Nov 7 |
Where these dates come from
ZIP code 52170 is matched to the NOAA station Lynxville Dam 9, WI, 16.1 km away, at 633 ft elevation (250 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Lynxville Dam 9, WI (used) | 633 ft | Apr 24 | Oct 17 |
| Waukon, IA | 1,275 ft | May 2 | Oct 11 |
| Prairie Du Chien, WI | 658 ft | Apr 28 | Oct 12 |
| Postville, IA | 1,165 ft | May 1 | Oct 3 |
Frost dates near Waterville
- Harpers Ferry, IA 52146 · last Apr 24, first Oct 17
- Waukon, IA 52172 · last May 2, first Oct 11
- Lansing, IA 52151 · last Apr 24, first Oct 17
- Lynxville, WI 54640 · last Apr 24, first Oct 17
- Monona, IA 52159 · last May 1, first Oct 3
- Marquette, IA 52158 · last Apr 28, first Oct 12
- Luana, IA 52156 · last May 1, first Oct 3
- Mc Gregor, IA 52157 · last Apr 28, first Oct 12
Frequently asked questions
- When is the last frost in Waterville, IA?
- For ZIP code 52170, the average last spring frost (32°F) is April 24, based on NOAA 1991-2020 climate normals for the Lynxville Dam 9, WI weather station. There is a 1-in-10 chance of a frost after May 8.
- When is the first frost in Waterville, IA?
- The average first fall frost (32°F) is October 17. There is a 1-in-10 chance of frost by October 4, so tender plants are at risk from that point on.
- How long is the growing season in 52170?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 175 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.