Last frost date in Ames, IA
In Ames, the last spring frost comes around April 26 in an average year. Wait until May 9 if you want 90% odds of no more frost. The first fall frost usually arrives about October 8, which leaves 164 frost-free days. An early freeze before September 23 happens one year in ten.
- Safe after (10% risk)
- May 9
- Average first frost
- Oct 8
- Frost-free season
- 164 days
- Hard freeze (28°F) ends
- Apr 14
No frost in the next 7 nights
Later than usual: the average first frost here is October 8.
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2253°
- FriOct 2357°
- SatOct 2455°
- SunOct 2551°
- MonOct 2645°
- TueOct 2743°
- WedOct 2845°
Planting calendar for Ames
Windows count forward or back from the average frost dates above. Click a crop for dates across Iowa.
TomatoesMay 3–May 17
PumpkinsMay 10–May 24
SunflowersApr 26–May 17
CucumbersMay 10–May 17
CornMay 3–May 17
Sweet potatoesMay 17–May 31
WatermelonMay 10–May 24
Green beansMay 3–May 24
ZucchiniMay 3–May 17
OkraMay 17–May 31
PeppersMay 10–May 24
BasilMay 3–May 17
Butternut squashMay 3–May 17
CantaloupeMay 10–May 24
EggplantMay 10–May 24
PotatoesMar 29–Apr 12
OnionsMar 15–Apr 5
CarrotsApr 5–May 10
LettuceApr 12–May 3
BroccoliMar 29–Apr 12
BeetsMar 29–May 10
PeasMar 15–Mar 29
CabbageMar 29–Apr 12
RadishesMar 22–May 3
Brussels sproutsApr 12–Apr 26
SpinachMar 15–Apr 5
CilantroApr 12–May 3
KaleMar 29–Apr 12
Collard greensMar 29–Apr 12
TurnipsMar 29–Apr 12
DillApr 26–May 10
CeleryMay 3–May 10
CauliflowerApr 12–Apr 26
LeeksApr 12–Apr 26
Swiss chardApr 12–May 10
ParsleyApr 12–May 3
Tulip bulbsSep 24–Oct 29
GarlicSep 17–Oct 22
Daffodil bulbsSep 10–Oct 22
StrawberriesMar 29–Apr 12
AsparagusMar 29–Apr 12Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Apr 11 | Apr 26 | May 9 | Sep 23 | Oct 8 | Oct 21 |
| Hard freeze, 28°F | Apr 1 | Apr 14 | May 1 | Oct 4 | Oct 19 | Oct 31 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Ames Municipal Airport (USW00094989) sits 2.4 miles from the center of Ames at 930 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Ames, IA?
The average last frost date in Ames is April 26, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 9.
When is the first frost in Ames?
The first frost in fall usually comes around October 8. One year in ten it arrives before September 23.
How long is the growing season in Ames?
About 164 days between the average last and first frost.
When should I plant tomatoes in Ames?
Plant tomato seedlings outside from May 3 to May 17. Start seeds indoors six to eight weeks earlier.
Nearby in Iowa
- AnkenyApr 23
- JohnstonApr 19
- AltoonaApr 23
- UrbandaleApr 19
- Des MoinesApr 18
- WaukeeApr 18
- West Des MoinesApr 18
- MarshalltownApr 28
- Fort DodgeApr 28
- Cedar FallsApr 27
- WaterlooApr 27
- Mason CityApr 29