Last frost date in Affton, MO

Average last frost
April 1

Expect the last frost in Affton around April 1. Frost after April 18 happens in only one year out of ten. The first fall frost usually arrives about November 4, which leaves 218 frost-free days. An early freeze before October 24 happens one year in ten.

Safe after (10% risk)
Apr 18
Average first frost
Nov 4
Frost-free season
218 days
Hard freeze (28°F) ends
Mar 22
Next 7 nights in Affton

No frost in the next 7 nights

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

  1. ThuOct 2249°
  2. FriOct 2348°
  3. SatOct 2450°
  4. SunOct 2552°
  5. MonOct 2651°
  6. TueOct 2748°
  7. WedOct 2849°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 1First frost Nov 4218 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND218 frost-free days
Frost risk through the year at St Louis Sci Center, 6.3 miles from Affton.

Planting calendar for Affton

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

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesApr 8–Apr 22
PumpkinsApr 15–Apr 29
SunflowersApr 1–Apr 22
CucumbersApr 15–Apr 22
CornApr 8–Apr 22
Sweet potatoesApr 22–May 6
WatermelonApr 15–Apr 29
Green beansApr 8–Apr 29
ZucchiniApr 8–Apr 22
OkraApr 22–May 6
PeppersApr 15–Apr 29
BasilApr 8–Apr 22
Butternut squashApr 8–Apr 22
CantaloupeApr 15–Apr 29
EggplantApr 15–Apr 29
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesMar 4–Mar 18
OnionsFeb 18–Mar 11
CarrotsMar 11–Apr 15
LettuceMar 18–Apr 8
BroccoliMar 4–Mar 18
BeetsMar 4–Apr 15
PeasFeb 18–Mar 4
CabbageMar 4–Mar 18
RadishesFeb 25–Apr 8
Brussels sproutsMar 18–Apr 1
SpinachFeb 18–Mar 11
CilantroMar 18–Apr 8
KaleMar 4–Mar 18
Collard greensMar 4–Mar 18
TurnipsMar 4–Mar 18
DillApr 1–Apr 15
CeleryApr 8–Apr 15
CauliflowerMar 18–Apr 1
LeeksMar 18–Apr 1
Swiss chardMar 18–Apr 15
ParsleyMar 18–Apr 8
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsOct 21–Nov 25
GarlicOct 14–Nov 18
Daffodil bulbsOct 7–Nov 18
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 4–Mar 18
AsparagusMar 4–Mar 18

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FMar 14Apr 1Apr 18Oct 24Nov 4Nov 21
Hard freeze, 28°FMar 5Mar 22Apr 7Nov 2Nov 15Dec 4

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 St Louis Sci Center (USC00237452) sits 6.3 miles from the center of Affton at 515 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 Affton, MO?

The average last frost date in Affton is April 1, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 18.

When is the first frost in Affton?

The first frost in fall usually comes around November 4. One year in ten it arrives before October 24.

How long is the growing season in Affton?

About 218 days between the average last and first frost.

When should I plant tomatoes in Affton?

Plant tomato seedlings outside from April 8 to April 22. Start seeds indoors six to eight weeks earlier.

Nearby in Missouri

All 41 cities in Missouri