Frost dates for 50701Waterloo, IA
The average last spring frost in Waterloo is April 27 and the average first fall frost is October 10, giving a typical growing season of about 165 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 27
- Average first fall frost
- Oct 10
- Growing season
- 165 days
Safer after May 10 (1-in-10 risk)
Possible by Sep 26 (1-in-10 risk)
Last frost typically in 177 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 23 · May 6 · May 17 | Sep 16 · Sep 30 · Oct 11 | 147 days | 100% |
| Frost / freeze (32°F) | Apr 11 · Apr 27 · May 10 | Sep 26 · Oct 10 · Oct 21 | 165 days | 100% |
| Hard freeze (28°F) | Apr 3 · Apr 16 · May 2 | Oct 6 · Oct 20 · Oct 31 | 185 days | 100% |
Planting calendar for Waterloo
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 27 – Jun 2 |
| Tomatoes | Transplant outdoors | May 13 – Jun 20 |
| Peppers | Start seeds indoors | Mar 27 – Apr 27 |
| Peppers | Transplant outdoors | May 27 – Jun 27 |
| Eggplant | Start seeds indoors | Apr 13 – May 12 |
| Eggplant | Transplant outdoors | May 27 – Jun 27 |
| Cucumbers | Sow outdoors | May 27 – Jun 30 |
| Summer squash | Sow outdoors | May 13 – Jun 27 |
| Winter squash & pumpkins | Sow outdoors | May 27 – Jun 27 |
| Snap beans | Sow outdoors | May 13 – Jul 23 |
| Sweet corn | Sow outdoors | May 13 – Jun 20 |
| Watermelon & cantaloupe | Sow outdoors | May 27 – Jun 27 |
| Okra | Sow outdoors | May 20 – Jun 12 |
| Peas | Sow outdoors (spring) | Mar 27 – May 12 |
| Potatoes | Plant outdoors (spring) | Mar 27 – May 27 |
| Onions | Start seeds indoors (spring) | Feb 13 – Mar 12 |
| Onions | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (spring) | Mar 9 – Apr 12 |
| Broccoli | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (fall) | Jun 10 – Jun 20 |
| Broccoli | Transplant outdoors (fall) | Jul 10 – Jul 21 |
| Cabbage | Start seeds indoors (spring) | Feb 27 – Mar 27 |
| Cabbage | Transplant outdoors (spring) | Mar 27 – Apr 27 |
| Cabbage | Start seeds indoors (fall) | May 31 – Jun 30 |
| Cabbage | Transplant outdoors (fall) | Jun 30 – Jul 31 |
| Leaf lettuce | Sow outdoors (spring) | Mar 27 – Jun 12 |
| Leaf lettuce | Sow outdoors (fall) | Jun 30 – Aug 16 |
| Spinach | Sow outdoors (spring) | Mar 20 – May 3 |
| Spinach | Sow outdoors (fall) | Jul 17 – Aug 21 |
| Radishes | Sow outdoors (spring) | Mar 27 – May 17 |
| Radishes | Sow outdoors (fall) | Jun 30 – Aug 31 |
| Kale | Sow outdoors (spring) | Apr 13 – May 3 |
| Kale | Sow outdoors (fall) | Jun 23 – Jul 31 |
| Carrots | Sow outdoors (spring) | Apr 27 – Jun 12 |
| Carrots | Sow outdoors (fall) | May 31 – Jul 16 |
| Garlic | Plant outdoors (fall) | Sep 30 – Oct 31 |
Where these dates come from
ZIP code 50701 is matched to the NOAA station Waterloo Muni Ap, IA, 9 km away, at 868 ft elevation (44 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Waterloo Muni Ap, IA (used) | 868 ft | Apr 27 | Oct 10 |
| Grundy Ctr, IA | 985 ft | Apr 29 | Oct 9 |
| Tripoli, IA | 1,055 ft | Apr 29 | Oct 9 |
| Independence #1, IA | 1,010 ft | Apr 30 | Oct 7 |
Frost dates near Waterloo
- Waterloo, IA 50702 · last Apr 27, first Oct 10
- Cedar Falls, IA 50614 · last Apr 27, first Oct 10
- Evansdale, IA 50707 · last Apr 27, first Oct 10
- Hudson, IA 50643 · last Apr 27, first Oct 10
- Raymond, IA 50667 · last Apr 27, first Oct 10
- Dewar, IA 50623 · last Apr 27, first Oct 10
- Gilbertville, IA 50634 · last Apr 27, first Oct 10
- Dike, IA 50624 · last Apr 29, first Oct 9
Frequently asked questions
- When is the last frost in Waterloo, IA?
- For ZIP code 50701, the average last spring frost (32°F) is April 27, based on NOAA 1991-2020 climate normals for the Waterloo Muni Ap, IA weather station. There is a 1-in-10 chance of a frost after May 10.
- When is the first frost in Waterloo, IA?
- The average first fall frost (32°F) is October 10. There is a 1-in-10 chance of frost by September 26, so tender plants are at risk from that point on.
- How long is the growing season in 50701?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 165 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.