Princeton, IA frost dates
Last spring frostApr 16median date
First fall frostOct 25median date
Growing season192 daysfrost-free
Hardiness zone5bZone 5b
How Princeton compares
- In 8 years out of 10, the last spring frost in Princeton falls between April 2 and April 30, a 28-day window. The first fall frost falls between October 11 and November 6.
- The median last frost is 12 days earlier than the Iowa median of Apr 28.
- Its 192-day growing season is among the longest of the 934 Iowa places with a regular frost season.
- The last frost is 15 days earlier than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 126 nights a year at or below 32°F.
- Compared with Davenport, IA, 23 km away, the last frost here is 7 days earlier than there and the growing season is 17 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 2 |
| 50% (median) | April 16 |
| 10% (safe for tender plants) | April 30 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 11 |
| 50% (median) | October 25 |
| 90% (late) | November 6 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Princeton, IA
Princeton, IA frost dates — last frost Apr 16, first frost Oct 25, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Jan 22 to Feb 5Transplant outside: Mar 19 to Apr 2
Start indoors: Feb 5 to Feb 19Transplant outside: Apr 30 to May 14
Start indoors: Feb 5 to Feb 19Transplant outside: Apr 30 to May 14
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 23 to May 7
Start indoors: Feb 19 to Mar 5Transplant outside: Mar 26 to Apr 9Sow outdoors: Mar 19 to Apr 23Plant for fall: Aug 30 to Sep 27
Start indoors: Feb 19 to Mar 5Transplant outside: Mar 19 to Apr 2Sow outdoors: Mar 19 to Apr 2Plant for fall: Aug 16 to Sep 6
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 2 to Apr 16Plant for fall: Jul 19 to Aug 9
Start indoors: Feb 19 to Mar 5Transplant outside: Mar 26 to Apr 9Plant for fall: Jul 19 to Aug 9
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 2 to Apr 16Plant for fall: Jul 19 to Aug 9
Start indoors: Mar 5 to Mar 19Transplant outside: May 7 to May 21Sow outdoors: May 7 to May 21
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 23 to May 7
Sow outdoors: Mar 5 to Mar 26Plant for fall: Aug 2 to Aug 23
Sow outdoors: Mar 5 to Mar 26Plant for fall: Aug 30 to Sep 20
Sow outdoors: Mar 12 to Apr 23Plant for fall: Sep 13 to Oct 4
Start indoors: Mar 19 to Mar 26Transplant outside: Apr 30 to May 7Sow outdoors: Apr 23 to May 7Plant for fall: Aug 9 to Aug 23
Start indoors: Mar 19 to Mar 26Sow outdoors: Apr 23 to May 7Plant for fall: Aug 16 to Aug 30
Start indoors: Mar 19 to Mar 26Sow outdoors: Apr 23 to May 7
Start indoors: Mar 19 to Mar 26Transplant outside: Apr 30 to May 14
Sow outdoors: Mar 26 to Apr 23Plant for fall: Aug 2 to Aug 16
Sow outdoors: Mar 26 to Apr 23Plant for fall: Aug 16 to Aug 30
Sow outdoors: Mar 26 to Apr 16
Sow outdoors: Apr 2 to Apr 30Plant for fall: Aug 16 to Aug 30
Sow outdoors: Apr 2 to Apr 23Plant for fall: Aug 30 to Sep 20
Sow outdoors: Apr 23 to May 14Plant for fall: Aug 9 to Aug 23
Sow outdoors: Apr 23 to May 7
Transplant outside: Apr 30 to May 21
Plant for fall: Oct 11 to Nov 15
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Princeton, IA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 22 – Feb 5 | Mar 19 – Apr 2 | — | — |
| Peppers | Feb 5 – Feb 19 | Apr 30 – May 14 | — | — |
| Eggplant | Feb 5 – Feb 19 | Apr 30 – May 14 | — | — |
| Tomatoes | Feb 19 – Mar 5 | Apr 23 – May 7 | — | — |
| Lettuce | Feb 19 – Mar 5 | Mar 26 – Apr 9 | Mar 19 – Apr 23 | Aug 30 – Sep 27 |
| Kale | Feb 19 – Mar 5 | Mar 19 – Apr 2 | Mar 19 – Apr 2 | Aug 16 – Sep 6 |
| Broccoli | Feb 19 – Mar 5 | Apr 2 – Apr 16 | — | Jul 19 – Aug 9 |
| Cabbage | Feb 19 – Mar 5 | Mar 26 – Apr 9 | — | Jul 19 – Aug 9 |
| Cauliflower | Feb 19 – Mar 5 | Apr 2 – Apr 16 | — | Jul 19 – Aug 9 |
| Okra | Mar 5 – Mar 19 | May 7 – May 21 | May 7 – May 21 | — |
| Basil | Mar 5 – Mar 19 | Apr 23 – May 7 | — | — |
| Peas | — | — | Mar 5 – Mar 26 | Aug 2 – Aug 23 |
| Spinach | — | — | Mar 5 – Mar 26 | Aug 30 – Sep 20 |
| Radishes | — | — | Mar 12 – Apr 23 | Sep 13 – Oct 4 |
| Cucumbers | Mar 19 – Mar 26 | Apr 30 – May 7 | Apr 23 – May 7 | Aug 9 – Aug 23 |
| Zucchini & Summer Squash | Mar 19 – Mar 26 | — | Apr 23 – May 7 | Aug 16 – Aug 30 |
| Winter Squash & Pumpkins | Mar 19 – Mar 26 | — | Apr 23 – May 7 | — |
| Melons & Watermelon | Mar 19 – Mar 26 | Apr 30 – May 14 | — | — |
| Carrots | — | — | Mar 26 – Apr 23 | Aug 2 – Aug 16 |
| Beets | — | — | Mar 26 – Apr 23 | Aug 16 – Aug 30 |
| Potatoes | — | — | Mar 26 – Apr 16 | — |
| Swiss Chard | — | — | Apr 2 – Apr 30 | Aug 16 – Aug 30 |
| Cilantro | — | — | Apr 2 – Apr 23 | Aug 30 – Sep 20 |
| Green Beans | — | — | Apr 23 – May 14 | Aug 9 – Aug 23 |
| Sweet Corn | — | — | Apr 23 – May 7 | — |
| Sweet Potatoes | — | Apr 30 – May 21 | — | — |
| Garlic | — | — | — | Oct 11 – Nov 15 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Le Claire L&D, IA weather station, 13 km away (elevation 577 ft (176 m)).
Frost dates near Princeton
- Le Claire Apr 16 · Oct 25
- Mc Causland Apr 22 · Oct 16
- Low Moor Apr 22 · Oct 16
- Pleasant Valley Apr 16 · Oct 25
- Camanche Apr 22 · Oct 16
- Long Grove Apr 21 · Oct 17
- Eldridge Apr 21 · Oct 17
- Bettendorf Apr 19 · Oct 22
- De Witt Apr 22 · Oct 16
- Davenport Apr 23 · Oct 15
Frequently asked questions
When is the last frost in Princeton, IA?
The median last spring frost in Princeton, IA is April 16. There is still about a 10% chance of frost after April 30, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Princeton, IA?
The median first fall frost is October 25, with about a 10% chance of frost before October 11.
How long is the growing season in Princeton, IA?
About 192 days between the median last spring frost and first fall frost.
What planting zone is Princeton, IA?
Princeton, IA is in USDA hardiness zone 5b.