Davenport, Iowa: planting zone & frost dates
Davenport is in USDA plant hardiness zone 5b, where the average coldest winter night reaches -15 to -10°F (-26.1 to -23.3°C). The typical last spring frost is around Apr 24 and the first fall frost around Oct 17.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 4 | Oct 7 |
| Typical planning date (30% risk) | Apr 24 | Oct 17 |
| Median (50%) | Apr 19 | Oct 22 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station ROCK ISLAND L&D 15, IL (USC00117391), 3.4 mi (5.4 km) from the city center and 85 ft lower than the city center (-26 m). Record used for the 1991–2020 normals: 30 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Davenport
All 6 ZIP codes covering Davenport are in zone 5b.
Vegetable planting calendar for Davenport
Dates are counted from the 30%-risk frost dates above (last frost Apr 24, first frost Oct 17). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 27 – Mar 13 | May 1 – May 15 | — | — |
| Pepper | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Lettuce | Mar 13 – Mar 27 | Apr 10 – May 1 | Mar 27 – May 8 | Aug 8 – Sep 5 |
| Green Beans | — | — | May 1 – Jun 5 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | May 1 – May 29 | — |
| Zucchini & Summer Squash | Mar 27 – Apr 3 | May 1 – May 15 | May 1 – May 22 | Jul 25 – Aug 8 |
| Cucumber | Mar 27 – Apr 3 | May 8 – May 15 | May 1 – May 22 | Jul 25 – Aug 8 |
| Carrot | — | — | Apr 3 – May 8 | Jul 25 – Aug 8 |
| Onion | Jan 30 – Feb 13 | Mar 27 – Apr 10 | — | — |
| Potato | — | Mar 27 – Apr 17 | — | — |
| Basil | Mar 13 – Mar 27 | May 8 – May 22 | May 8 – May 29 | — |
| Spinach | — | — | Mar 13 – Apr 10 | Aug 22 – Sep 19 |
| Kale | Feb 27 – Mar 13 | Mar 27 – Apr 17 | Mar 27 – Apr 17 | Aug 8 – Sep 5 |
| Broccoli | Feb 27 – Mar 13 | Apr 10 – May 1 | — | Jul 25 – Aug 8 |
| Peas | — | — | Mar 13 – Apr 3 | Aug 8 – Aug 22 |
| Eggplant | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Cabbage | Feb 27 – Mar 13 | Mar 27 – Apr 10 | — | Jul 25 – Aug 8 |
| Radish | — | — | Mar 20 – May 8 | Sep 5 – Oct 3 |
| Strawberry | — | Mar 27 – Apr 17 | — | — |
| Beets | — | — | Apr 3 – May 15 | Aug 8 – Aug 22 |
Nearby cities in Iowa
- Iowa City — zone 5b, last frost Apr 28, first frost Oct 13
- Cedar Rapids — zone 5a, last frost May 3, first frost Oct 5
- Ankeny — zone 5b, last frost Apr 29, first frost Oct 9
- Des Moines — zone 5b, last frost Apr 24, first frost Oct 14
- Sioux City — zone 5a, last frost May 4, first frost Oct 1
More: all Iowa cities · other zone 5b cities: Madison, WI, Des Moines, IA, Aurora, IL, Fort Collins, CO, Naperville, IL, Rockford, IL, Elgin, IL, Greeley, CO
Davenport gardening questions
When is the last frost in Davenport, IA?
Plan around Apr 24. At NOAA's Rock Island L&d 15, IL station, 3.4 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 19, and after May 4 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 8. The last frost is fairly predictable here: only 28 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Davenport, IA?
Start seeds indoors Feb 27 – Mar 13 and set transplants outside May 1 – May 15, once nights stay above 50°F and the soil is near 60°F. That leaves 176 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Davenport?
About 184 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 164 days, and in 1 year in 10 it runs 203 days or more. In fall there is a 10% chance of frost by Oct 7 and a 30% chance by Oct 17. That ranks 2nd longest of 6 Iowa cities on this site.
When should I plant a fall garden in Davenport?
Count back from the first fall frost (Oct 17): transplant broccoli Jul 25 – Aug 8; sow kale Aug 8 – Sep 5; sow lettuce Aug 8 – Sep 5; sow radishes Sep 5 – Oct 3. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 31. How the math works: succession and fall planting.
Did Davenport's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Davenport is zone 5b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Davenport compare with Iowa City, IA?
Both are in zone 5b. The typical last spring frost in Davenport (Apr 24) comes about 4 days earlier than in Iowa City, IA (Apr 28), 48 miles away, and the first fall frost is Oct 17 versus Oct 13. The two cities use different NOAA stations.