Frost dates for Ames, IA
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 26
typical year
Safe to plant
May 9
frost is over in 9 of 10 years
First fall frost
October 8
typical year
Growing season
164 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 29 – Apr 12 | – |
| Spinach | – | Mar 15 – Apr 5 | Aug 13 – 27 |
| Lettuce | – | Mar 29 – Apr 19 | Aug 13 – 27 |
| Radishes | – | Mar 29 – May 10 | Aug 27 – Sep 10 |
| Onions | – | Mar 29 – Apr 12 | – |
| Potatoes | – | Apr 5 – 19 | – |
| Carrots | – | Apr 5 – 26 | Jul 16 – 30 |
| Beets | – | Mar 29 – Apr 12 | Jul 30 – Aug 13 |
| Kale | Feb 15 – Mar 1 | Mar 29 – Apr 12 | Jul 30 – Aug 13 |
| Broccoli | Feb 15 – Mar 1 | Apr 12 – 26 | Jul 30 – Aug 13 |
| Cabbage | Feb 1 – 15 | Mar 29 – Apr 12 | Jul 30 – Aug 13 |
| Garlic | – | – | Aug 27 – Sep 17 |
| Warm-season crops | |||
| Tomatoes | Mar 14 – 28 | May 9 – 23 | – |
| Peppers | Mar 7 – 21 | May 16 – 30 | – |
| Cucumbers | – | May 9 – 30 | – |
| Zucchini | – | May 9 – Jun 6 | – |
| Pumpkins | – | May 9 – 30 | – |
| Green beans | – | May 9 – Jul 30 | – |
| Sweet corn | – | May 9 – Jun 6 | – |
| Basil | Apr 4 – 18 | May 16 – 23 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 9 | April 26 | April 11 |
| Fall frost before | September 23 | October 8 | October 21 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 14 (May 1 in a late year), and the first one in fall around October 19.
Towns that use these dates
This is the nearest NOAA station with frost records for 6 towns.
Ames, Story City, Gilbert, Roland, Kelley, Randall
Where these dates come from
NOAA weather station AMES MUNI AP, IA US (USW00094989), 1991–2020 climate normals. It's the nearest station for 7 zip codes, all within 17 miles:
50010, 50012, 50013, 50105, 50134, 50231, 50248
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.