Last frost date in Clinton, IA

Average last frost
April 22

Expect the last frost in Clinton around April 22. Frost after May 8 happens in only one year out of ten. The first fall frost usually arrives about October 16, which leaves 175 frost-free days. An early freeze before October 2 happens one year in ten.

Safe after (10% risk)
May 8
Average first frost
Oct 16
Frost-free season
175 days
Hard freeze (28°F) ends
Apr 13
Next 7 nights in Clinton

No frost in the next 7 nights

Later than usual: the average first frost here is October 16.

National Weather Service forecast, updated Oct 22, 12:57 UTC

  1. ThuOct 2250°
  2. FriOct 2350°
  3. SatOct 2451°
  4. SunOct 2551°
  5. MonOct 2647°
  6. TueOct 2743°
  7. WedOct 2845°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 22First frost Oct 16175 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND175 frost-free days
Frost risk through the year at Clinton #1, 3.5 miles from Clinton.

Planting calendar for Clinton

Windows count forward or back from the average frost dates above. Click a crop for dates across Iowa.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesApr 29–May 13
PumpkinsMay 6–May 20
SunflowersApr 22–May 13
CucumbersMay 6–May 13
CornApr 29–May 13
Sweet potatoesMay 13–May 27
WatermelonMay 6–May 20
Green beansApr 29–May 20
ZucchiniApr 29–May 13
OkraMay 13–May 27
PeppersMay 6–May 20
BasilApr 29–May 13
Butternut squashApr 29–May 13
CantaloupeMay 6–May 20
EggplantMay 6–May 20
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesMar 25–Apr 8
OnionsMar 11–Apr 1
CarrotsApr 1–May 6
LettuceApr 8–Apr 29
BroccoliMar 25–Apr 8
BeetsMar 25–May 6
PeasMar 11–Mar 25
CabbageMar 25–Apr 8
RadishesMar 18–Apr 29
Brussels sproutsApr 8–Apr 22
SpinachMar 11–Apr 1
CilantroApr 8–Apr 29
KaleMar 25–Apr 8
Collard greensMar 25–Apr 8
TurnipsMar 25–Apr 8
DillApr 22–May 6
CeleryApr 29–May 6
CauliflowerApr 8–Apr 22
LeeksApr 8–Apr 22
Swiss chardApr 8–May 6
ParsleyApr 8–Apr 29
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsOct 2–Nov 6
GarlicSep 25–Oct 30
Daffodil bulbsSep 18–Oct 30
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 25–Apr 8
AsparagusMar 25–Apr 8

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 9Apr 22May 8Oct 2Oct 16Oct 28
Hard freeze, 28°FMar 31Apr 13Apr 29Oct 11Oct 25Nov 5

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 Clinton #1 (USC00131635) sits 3.5 miles from the center of Clinton at 585 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 Clinton, IA?

The average last frost date in Clinton is April 22, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 8.

When is the first frost in Clinton?

The first frost in fall usually comes around October 16. One year in ten it arrives before October 2.

How long is the growing season in Clinton?

About 175 days between the average last and first frost.

When should I plant tomatoes in Clinton?

Plant tomato seedlings outside from April 29 to May 13. Start seeds indoors six to eight weeks earlier.

Nearby in Iowa

All 27 cities in Iowa