Ames, IA frost dates
Last spring frostApr 26median date
First fall frostOct 8median date
Growing season165 daysfrost-free
Hardiness zone5bZone 5b
How Ames compares
- In 8 years out of 10, the last spring frost in Ames falls between April 11 and May 9, a 28-day window. The first fall frost falls between September 23 and October 21.
- The median last frost is 2 days earlier than the Iowa median of Apr 28.
- Its 165-day growing season is longer than 46% 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 147 nights a year at or below 32°F.
- Compared with Des Moines, IA, 43 km away, the last frost here is 3 days later than there and the growing season is 10 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 11 |
| 50% (median) | April 26 |
| 10% (safe for tender plants) | May 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 23 |
| 50% (median) | October 8 |
| 90% (late) | October 21 |
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 Ames, IA
Ames, IA frost dates — last frost Apr 26, first frost Oct 8, 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 13 to Sep 10
Start indoors: Mar 1 to Mar 15Transplant outside: Mar 29 to Apr 12Sow outdoors: Mar 29 to Apr 12Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 5 to Apr 19Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 1 to Mar 15Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 2 to Jul 23
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 16 to Aug 6
Sow outdoors: Mar 15 to Apr 5Plant for fall: Aug 13 to Sep 3
Sow outdoors: Mar 22 to May 3Plant for fall: Aug 27 to Sep 17
Start indoors: Mar 29 to Apr 5Transplant outside: May 10 to May 17Sow outdoors: May 3 to May 17Plant for fall: Jul 23 to Aug 6
Start indoors: Mar 29 to Apr 5Sow outdoors: May 3 to May 17Plant for fall: Jul 30 to Aug 13
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 16 to Jul 30
Sow outdoors: Apr 5 to May 3Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 5 to Apr 26
Sow outdoors: Apr 12 to May 10Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 12 to May 3Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 3 to May 24Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 3 to May 17
Transplant outside: May 10 to May 31
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Ames, 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 13 – Sep 10 |
| Kale | Mar 1 – Mar 15 | Mar 29 – Apr 12 | Mar 29 – Apr 12 | Jul 30 – Aug 20 |
| Broccoli | Mar 1 – Mar 15 | Apr 12 – Apr 26 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 1 – Mar 15 | Apr 5 – Apr 19 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 1 – Mar 15 | Apr 12 – Apr 26 | — | Jul 2 – Jul 23 |
| 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 16 – Aug 6 |
| Spinach | — | — | Mar 15 – Apr 5 | Aug 13 – Sep 3 |
| Radishes | — | — | Mar 22 – May 3 | Aug 27 – Sep 17 |
| Cucumbers | Mar 29 – Apr 5 | May 10 – May 17 | May 3 – May 17 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Mar 29 – Apr 5 | — | May 3 – May 17 | Jul 30 – Aug 13 |
| 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 16 – Jul 30 |
| Beets | — | — | Apr 5 – May 3 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 5 – Apr 26 | — |
| Swiss Chard | — | — | Apr 12 – May 10 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 12 – May 3 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 3 – May 24 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 3 – May 17 | — |
| Sweet Potatoes | — | May 10 – May 31 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
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 Ames Muni Ap, IA weather station, 5 km away (elevation 932 ft (284 m)).
ZIP codes in Ames: 50010 50011 50012 50013 50014
Frost dates near Ames
- Gilbert Apr 26 · Oct 8
- Kelley Apr 26 · Oct 8
- Nevada Apr 24 · Oct 12
- Huxley Apr 26 · Oct 12
- Cambridge Apr 26 · Oct 12
- Story City Apr 26 · Oct 8
- Roland Apr 26 · Oct 8
- Slater Apr 26 · Oct 12
- Sheldahl Apr 19 · Oct 18
- Luther Apr 23 · Oct 14
Frequently asked questions
When is the last frost in Ames, IA?
The median last spring frost in Ames, IA is April 26. There is still about a 10% chance of frost after May 9, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ames, IA?
The median first fall frost is October 8, with about a 10% chance of frost before September 23.
How long is the growing season in Ames, IA?
About 165 days between the median last spring frost and first fall frost.
What planting zone is Ames, IA?
Ames, IA is in USDA hardiness zone 5b.