Norwalk, IA frost dates
Last spring frostApr 18median date
First fall frostOct 20median date
Growing season185 daysfrost-free
Hardiness zone5bZone 5b
How Norwalk compares
- In 8 years out of 10, the last spring frost in Norwalk falls between April 4 and May 2, a 28-day window. The first fall frost falls between October 4 and November 1.
- The median last frost is 10 days earlier than the Iowa median of Apr 28.
- Its 185-day growing season is longer than 93% of the 934 Iowa places with a regular frost season (state median 165 days).
- The last frost is 13 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 128 nights a year at or below 32°F.
- Norwalk shares its weather station with West Des Moines, IA, 14 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 4 |
| 50% (median) | April 18 |
| 10% (safe for tender plants) | May 2 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 4 |
| 50% (median) | October 20 |
| 90% (late) | November 1 |
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 Norwalk, IA
Norwalk, IA frost dates — last frost Apr 18, first frost Oct 20, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Jan 24 to Feb 7Transplant outside: Mar 21 to Apr 4
Start indoors: Feb 7 to Feb 21Transplant outside: May 2 to May 16
Start indoors: Feb 7 to Feb 21Transplant outside: May 2 to May 16
Start indoors: Feb 21 to Mar 7Transplant outside: Apr 25 to May 9
Start indoors: Feb 21 to Mar 7Transplant outside: Mar 28 to Apr 11Sow outdoors: Mar 21 to Apr 25Plant for fall: Aug 25 to Sep 22
Start indoors: Feb 21 to Mar 7Transplant outside: Mar 21 to Apr 4Sow outdoors: Mar 21 to Apr 4Plant for fall: Aug 11 to Sep 1
Start indoors: Feb 21 to Mar 7Transplant outside: Apr 4 to Apr 18Plant for fall: Jul 14 to Aug 4
Start indoors: Feb 21 to Mar 7Transplant outside: Mar 28 to Apr 11Plant for fall: Jul 14 to Aug 4
Start indoors: Feb 21 to Mar 7Transplant outside: Apr 4 to Apr 18Plant for fall: Jul 14 to Aug 4
Start indoors: Mar 7 to Mar 21Transplant outside: May 9 to May 23Sow outdoors: May 9 to May 23
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 25 to May 9
Sow outdoors: Mar 7 to Mar 28Plant for fall: Jul 28 to Aug 18
Sow outdoors: Mar 7 to Mar 28Plant for fall: Aug 25 to Sep 15
Sow outdoors: Mar 14 to Apr 25Plant for fall: Sep 8 to Sep 29
Start indoors: Mar 21 to Mar 28Transplant outside: May 2 to May 9Sow outdoors: Apr 25 to May 9Plant for fall: Aug 4 to Aug 18
Start indoors: Mar 21 to Mar 28Sow outdoors: Apr 25 to May 9Plant for fall: Aug 11 to Aug 25
Start indoors: Mar 21 to Mar 28Sow outdoors: Apr 25 to May 9
Start indoors: Mar 21 to Mar 28Transplant outside: May 2 to May 16
Sow outdoors: Mar 28 to Apr 25Plant for fall: Jul 28 to Aug 11
Sow outdoors: Mar 28 to Apr 25Plant for fall: Aug 11 to Aug 25
Sow outdoors: Mar 28 to Apr 18
Sow outdoors: Apr 4 to May 2Plant for fall: Aug 11 to Aug 25
Sow outdoors: Apr 4 to Apr 25Plant for fall: Aug 25 to Sep 15
Sow outdoors: Apr 25 to May 16Plant for fall: Aug 4 to Aug 18
Sow outdoors: Apr 25 to May 9
Transplant outside: May 2 to May 23
Plant for fall: Oct 6 to Nov 10
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Norwalk, IA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 24 – Feb 7 | Mar 21 – Apr 4 | — | — |
| Peppers | Feb 7 – Feb 21 | May 2 – May 16 | — | — |
| Eggplant | Feb 7 – Feb 21 | May 2 – May 16 | — | — |
| Tomatoes | Feb 21 – Mar 7 | Apr 25 – May 9 | — | — |
| Lettuce | Feb 21 – Mar 7 | Mar 28 – Apr 11 | Mar 21 – Apr 25 | Aug 25 – Sep 22 |
| Kale | Feb 21 – Mar 7 | Mar 21 – Apr 4 | Mar 21 – Apr 4 | Aug 11 – Sep 1 |
| Broccoli | Feb 21 – Mar 7 | Apr 4 – Apr 18 | — | Jul 14 – Aug 4 |
| Cabbage | Feb 21 – Mar 7 | Mar 28 – Apr 11 | — | Jul 14 – Aug 4 |
| Cauliflower | Feb 21 – Mar 7 | Apr 4 – Apr 18 | — | Jul 14 – Aug 4 |
| Okra | Mar 7 – Mar 21 | May 9 – May 23 | May 9 – May 23 | — |
| Basil | Mar 7 – Mar 21 | Apr 25 – May 9 | — | — |
| Peas | — | — | Mar 7 – Mar 28 | Jul 28 – Aug 18 |
| Spinach | — | — | Mar 7 – Mar 28 | Aug 25 – Sep 15 |
| Radishes | — | — | Mar 14 – Apr 25 | Sep 8 – Sep 29 |
| Cucumbers | Mar 21 – Mar 28 | May 2 – May 9 | Apr 25 – May 9 | Aug 4 – Aug 18 |
| Zucchini & Summer Squash | Mar 21 – Mar 28 | — | Apr 25 – May 9 | Aug 11 – Aug 25 |
| Winter Squash & Pumpkins | Mar 21 – Mar 28 | — | Apr 25 – May 9 | — |
| Melons & Watermelon | Mar 21 – Mar 28 | May 2 – May 16 | — | — |
| Carrots | — | — | Mar 28 – Apr 25 | Jul 28 – Aug 11 |
| Beets | — | — | Mar 28 – Apr 25 | Aug 11 – Aug 25 |
| Potatoes | — | — | Mar 28 – Apr 18 | — |
| Swiss Chard | — | — | Apr 4 – May 2 | Aug 11 – Aug 25 |
| Cilantro | — | — | Apr 4 – Apr 25 | Aug 25 – Sep 15 |
| Green Beans | — | — | Apr 25 – May 16 | Aug 4 – Aug 18 |
| Sweet Corn | — | — | Apr 25 – May 9 | — |
| Sweet Potatoes | — | May 2 – May 23 | — | — |
| Garlic | — | — | — | Oct 6 – Nov 10 |
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 Des Moines Intl Ap, IA weather station, 5 km away (elevation 958 ft (292 m)).
Frost dates near Norwalk
- Cumming Apr 18 · Oct 20
- Prole Apr 24 · Oct 12
- Carlisle Apr 18 · Oct 20
- West Des Moines Apr 18 · Oct 20
- Windsor Heights Apr 18 · Oct 20
- Martensdale Apr 24 · Oct 12
- Clive Apr 18 · Oct 20
- Pleasant Hill Apr 18 · Oct 20
- Urbandale Apr 19 · Oct 18
- Bevington Apr 24 · Oct 12
Frequently asked questions
When is the last frost in Norwalk, IA?
The median last spring frost in Norwalk, IA is April 18. There is still about a 10% chance of frost after May 2, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Norwalk, IA?
The median first fall frost is October 20, with about a 10% chance of frost before October 4.
How long is the growing season in Norwalk, IA?
About 185 days between the median last spring frost and first fall frost.
What planting zone is Norwalk, IA?
Norwalk, IA is in USDA hardiness zone 5b.