Frost dates for 52768Princeton, IA
The average last spring frost in Princeton is April 16 and the average first fall frost is October 25, giving a typical growing season of about 190 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 16
- Average first fall frost
- Oct 25
- Growing season
- 190 days
Safer after Apr 30 (1-in-10 risk)
Possible by Oct 11 (1-in-10 risk)
Last frost typically in 168 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 11 · Apr 27 · May 8 | Oct 1 · Oct 15 · Oct 28 | 171 days | 100% |
| Frost / freeze (32°F) | Apr 2 · Apr 16 · Apr 30 | Oct 11 · Oct 25 · Nov 6 | 190 days | 100% |
| Hard freeze (28°F) | Mar 21 · Apr 6 · Apr 21 | Oct 23 · Nov 2 · Nov 18 | 210 days | 100% |
Planting calendar for Princeton
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 16 – May 22 |
| Tomatoes | Transplant outdoors | May 2 – Jul 5 |
| Peppers | Start seeds indoors | Mar 16 – Apr 16 |
| Peppers | Transplant outdoors | May 16 – Jun 16 |
| Eggplant | Start seeds indoors | Apr 2 – May 1 |
| Eggplant | Transplant outdoors | May 16 – Jun 16 |
| Cucumbers | Sow outdoors | May 16 – Jul 15 |
| Summer squash | Sow outdoors | May 2 – Jun 16 |
| Winter squash & pumpkins | Sow outdoors | May 16 – Jun 16 |
| Snap beans | Sow outdoors | May 2 – Aug 7 |
| Sweet corn | Sow outdoors | May 2 – Jul 5 |
| Watermelon & cantaloupe | Sow outdoors | May 16 – Jun 16 |
| Okra | Sow outdoors | May 9 – Jun 1 |
| Peas | Sow outdoors (spring) | Mar 16 – May 1 |
| Potatoes | Plant outdoors (spring) | Mar 16 – May 16 |
| Onions | Start seeds indoors (spring) | Feb 2 – Mar 1 |
| Onions | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (spring) | Feb 26 – Apr 1 |
| Broccoli | Transplant outdoors (spring) | Apr 2 – May 1 |
| Broccoli | Start seeds indoors (fall) | Jun 25 – Jul 5 |
| Broccoli | Transplant outdoors (fall) | Jul 25 – Aug 5 |
| Cabbage | Start seeds indoors (spring) | Feb 16 – Mar 16 |
| Cabbage | Transplant outdoors (spring) | Mar 16 – Apr 16 |
| Cabbage | Start seeds indoors (fall) | Jun 15 – Jul 15 |
| Cabbage | Transplant outdoors (fall) | Jul 15 – Aug 15 |
| Leaf lettuce | Sow outdoors (spring) | Mar 16 – Jun 1 |
| Leaf lettuce | Sow outdoors (fall) | Jul 15 – Aug 31 |
| Spinach | Sow outdoors (spring) | Mar 9 – Apr 22 |
| Spinach | Sow outdoors (fall) | Aug 1 – Sep 5 |
| Radishes | Sow outdoors (spring) | Mar 16 – May 6 |
| Radishes | Sow outdoors (fall) | Jul 15 – Sep 15 |
| Kale | Sow outdoors (spring) | Apr 2 – Apr 22 |
| Kale | Sow outdoors (fall) | Jul 8 – Aug 15 |
| Carrots | Sow outdoors (spring) | Apr 16 – Jun 1 |
| Carrots | Sow outdoors (fall) | Jun 15 – Jul 31 |
| Garlic | Plant outdoors (fall) | Oct 15 – Nov 15 |
Where these dates come from
ZIP code 52768 is matched to the NOAA station Le Claire L&D 14, IA, 12.6 km away, at 577 ft elevation (99 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Le Claire L&D 14, IA (used) | 577 ft | Apr 16 | Oct 25 |
| Clinton #1, IA | 585 ft | Apr 22 | Oct 16 |
| Davenport Wfo, IA | 750 ft | Apr 21 | Oct 17 |
| Davenport, IA | 754 ft | Apr 23 | Oct 15 |
Frost dates near Princeton
- Cordova, IL 61242 · last Apr 22, first Oct 16
- Le Claire, IA 52753 · last Apr 16, first Oct 25
- Mc Causland, IA 52758 · last Apr 22, first Oct 16
- Port Byron, IL 61275 · last Apr 16, first Oct 25
- Rapids City, IL 61278 · last Apr 16, first Oct 25
- Low Moor, IA 52757 · last Apr 22, first Oct 16
- Pleasant Valley, IA 52767 · last Apr 16, first Oct 25
- Camanche, IA 52730 · last Apr 22, first Oct 16
Frequently asked questions
- When is the last frost in Princeton, IA?
- For ZIP code 52768, the average last spring frost (32°F) is April 16, based on NOAA 1991-2020 climate normals for the Le Claire L&D 14, IA weather station. There is a 1-in-10 chance of a frost after April 30.
- When is the first frost in Princeton, IA?
- The average first fall frost (32°F) is October 25. There is a 1-in-10 chance of frost by October 11, so tender plants are at risk from that point on.
- How long is the growing season in 52768?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 190 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.