Winfield, IA frost dates
Last spring frostApr 26median date
First fall frostOct 10median date
Growing season167 daysfrost-free
Hardiness zone5bZone 5b
How Winfield compares
- In 8 years out of 10, the last spring frost in Winfield falls between April 11 and May 11, a 30-day window. The first fall frost falls between September 23 and October 22.
- The median last frost is 2 days earlier than the Iowa median of Apr 28.
- Its 167-day growing season is longer than 59% of the 934 Iowa places with a regular frost season (state median 165 days).
- The last frost is 5 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 134 nights a year at or below 32°F.
- Compared with Iowa City, IA, 58 km away, the last frost here is 5 days later than there and the growing season is 13 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 11 |
| 50% (median) | April 26 |
| 10% (safe for tender plants) | May 11 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 23 |
| 50% (median) | October 10 |
| 90% (late) | October 22 |
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 Winfield, IA
Winfield, IA frost dates — last frost Apr 26, first frost Oct 10, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Feb 1 to Feb 15Transplant outside: Mar 29 to Apr 12
Start indoors: Feb 15 to Mar 1Transplant outside: May 10 to May 24
Start indoors: Feb 15 to Mar 1Transplant outside: May 10 to May 24
Start indoors: Mar 1 to Mar 15Transplant outside: May 3 to May 17
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 5 to Apr 19Sow outdoors: Mar 29 to May 3Plant for fall: Aug 15 to Sep 12
Start indoors: Mar 1 to Mar 15Transplant outside: Mar 29 to Apr 12Sow outdoors: Mar 29 to Apr 12Plant for fall: Aug 1 to Aug 22
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 5 to Apr 19Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 15 to Mar 29Transplant outside: May 17 to May 31Sow outdoors: May 17 to May 31
Start indoors: Mar 15 to Mar 29Transplant outside: May 3 to May 17
Sow outdoors: Mar 15 to Apr 5Plant for fall: Jul 18 to Aug 8
Sow outdoors: Mar 15 to Apr 5Plant for fall: Aug 15 to Sep 5
Sow outdoors: Mar 22 to May 3Plant for fall: Aug 29 to Sep 19
Start indoors: Mar 29 to Apr 5Transplant outside: May 10 to May 17Sow outdoors: May 3 to May 17Plant for fall: Jul 25 to Aug 8
Start indoors: Mar 29 to Apr 5Sow outdoors: May 3 to May 17Plant for fall: Aug 1 to Aug 15
Start indoors: Mar 29 to Apr 5Sow outdoors: May 3 to May 17
Start indoors: Mar 29 to Apr 5Transplant outside: May 10 to May 24
Sow outdoors: Apr 5 to May 3Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 5 to May 3Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 5 to Apr 26
Sow outdoors: Apr 12 to May 10Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 12 to May 3Plant for fall: Aug 15 to Sep 5
Sow outdoors: May 3 to May 24Plant for fall: Jul 25 to Aug 8
Sow outdoors: May 3 to May 17
Transplant outside: May 10 to May 31
Plant for fall: Sep 26 to Oct 31
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Winfield, IA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 1 – Feb 15 | Mar 29 – Apr 12 | — | — |
| Peppers | Feb 15 – Mar 1 | May 10 – May 24 | — | — |
| Eggplant | Feb 15 – Mar 1 | May 10 – May 24 | — | — |
| Tomatoes | Mar 1 – Mar 15 | May 3 – May 17 | — | — |
| Lettuce | Mar 1 – Mar 15 | Apr 5 – Apr 19 | Mar 29 – May 3 | Aug 15 – Sep 12 |
| Kale | Mar 1 – Mar 15 | Mar 29 – Apr 12 | Mar 29 – Apr 12 | Aug 1 – Aug 22 |
| Broccoli | Mar 1 – Mar 15 | Apr 12 – Apr 26 | — | Jul 4 – Jul 25 |
| Cabbage | Mar 1 – Mar 15 | Apr 5 – Apr 19 | — | Jul 4 – Jul 25 |
| Cauliflower | Mar 1 – Mar 15 | Apr 12 – Apr 26 | — | Jul 4 – Jul 25 |
| Okra | Mar 15 – Mar 29 | May 17 – May 31 | May 17 – May 31 | — |
| Basil | Mar 15 – Mar 29 | May 3 – May 17 | — | — |
| Peas | — | — | Mar 15 – Apr 5 | Jul 18 – Aug 8 |
| Spinach | — | — | Mar 15 – Apr 5 | Aug 15 – Sep 5 |
| Radishes | — | — | Mar 22 – May 3 | Aug 29 – Sep 19 |
| Cucumbers | Mar 29 – Apr 5 | May 10 – May 17 | May 3 – May 17 | Jul 25 – Aug 8 |
| Zucchini & Summer Squash | Mar 29 – Apr 5 | — | May 3 – May 17 | Aug 1 – Aug 15 |
| Winter Squash & Pumpkins | Mar 29 – Apr 5 | — | May 3 – May 17 | — |
| Melons & Watermelon | Mar 29 – Apr 5 | May 10 – May 24 | — | — |
| Carrots | — | — | Apr 5 – May 3 | Jul 18 – Aug 1 |
| Beets | — | — | Apr 5 – May 3 | Aug 1 – Aug 15 |
| Potatoes | — | — | Apr 5 – Apr 26 | — |
| Swiss Chard | — | — | Apr 12 – May 10 | Aug 1 – Aug 15 |
| Cilantro | — | — | Apr 12 – May 3 | Aug 15 – Sep 5 |
| Green Beans | — | — | May 3 – May 24 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | May 3 – May 17 | — |
| Sweet Potatoes | — | May 10 – May 31 | — | — |
| Garlic | — | — | — | Sep 26 – Oct 31 |
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 Columbus Junction, IA weather station, 18 km away (elevation 591 ft (180 m)).
Frost dates near Winfield
- Olds Apr 30 · Oct 10
- Swedesburg Apr 30 · Oct 10
- Mount Union Apr 30 · Oct 10
- Crawfordsville Apr 28 · Oct 11
- Morning Sun Apr 14 · Oct 24
- Columbus City Apr 26 · Oct 10
- Wayland Apr 28 · Oct 11
- Yarmouth Apr 30 · Oct 10
- Mount Pleasant Apr 30 · Oct 10
- Columbus Junction Apr 26 · Oct 10
Frequently asked questions
When is the last frost in Winfield, IA?
The median last spring frost in Winfield, IA is April 26. There is still about a 10% chance of frost after May 11, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Winfield, IA?
The median first fall frost is October 10, with about a 10% chance of frost before September 23.
How long is the growing season in Winfield, IA?
About 167 days between the median last spring frost and first fall frost.
What planting zone is Winfield, IA?
Winfield, IA is in USDA hardiness zone 5b.