Last frost date in American Fork, UT

Average last frost
April 17

The average last frost in American Fork is April 17. By May 7 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about October 25, which leaves 188 frost-free days. An early freeze before October 10 happens one year in ten.

Safe after (10% risk)
May 7
Average first frost
Oct 25
Frost-free season
188 days
Hard freeze (28°F) ends
Mar 30
Next 7 nights in American Fork

No frost in the next 7 nights

National Weather Service forecast, updated Oct 22, 12:24 UTC

  1. ThuOct 2244°
  2. FriOct 2339°
  3. SatOct 2439°
  4. SunOct 2538°
  5. MonOct 2640°
  6. TueOct 2739°
  7. WedOct 2842°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 17First frost Oct 25188 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND188 frost-free days
Frost risk through the year at Pleasant Grove, 3.3 miles from American Fork.

Planting calendar for American Fork

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

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesApr 24–May 8
PumpkinsMay 1–May 15
SunflowersApr 17–May 8
CucumbersMay 1–May 8
CornApr 24–May 8
Sweet potatoesMay 8–May 22
WatermelonMay 1–May 15
Green beansApr 24–May 15
ZucchiniApr 24–May 8
OkraMay 8–May 22
PeppersMay 1–May 15
BasilApr 24–May 8
Butternut squashApr 24–May 8
CantaloupeMay 1–May 15
EggplantMay 1–May 15
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesMar 20–Apr 3
OnionsMar 6–Mar 27
CarrotsMar 27–May 1
LettuceApr 3–Apr 24
BroccoliMar 20–Apr 3
BeetsMar 20–May 1
PeasMar 6–Mar 20
CabbageMar 20–Apr 3
RadishesMar 13–Apr 24
Brussels sproutsApr 3–Apr 17
SpinachMar 6–Mar 27
CilantroApr 3–Apr 24
KaleMar 20–Apr 3
Collard greensMar 20–Apr 3
TurnipsMar 20–Apr 3
DillApr 17–May 1
CeleryApr 24–May 1
CauliflowerApr 3–Apr 17
LeeksApr 3–Apr 17
Swiss chardApr 3–May 1
ParsleyApr 3–Apr 24
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsOct 11–Nov 15
GarlicOct 4–Nov 8
Daffodil bulbsSep 27–Nov 8
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 20–Apr 3
AsparagusMar 20–Apr 3

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FMar 30Apr 17May 7Oct 10Oct 25Nov 8
Hard freeze, 28°FMar 8Mar 30Apr 17Oct 21Nov 5Nov 19

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 Pleasant Grove (USC00426919) sits 3.3 miles from the center of American Fork at 4,692 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 American Fork, UT?

The average last frost date in American Fork is April 17, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 7.

When is the first frost in American Fork?

The first frost in fall usually comes around October 25. One year in ten it arrives before October 10.

How long is the growing season in American Fork?

About 188 days between the average last and first frost.

When should I plant tomatoes in American Fork?

Plant tomato seedlings outside from April 24 to May 8. Start seeds indoors six to eight weeks earlier.

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