Last frost date in Chambersburg, PA

Average last frost
April 18

The average last frost in Chambersburg is April 18. By May 5 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 5
Average first frost
Oct 25
Frost-free season
188 days
Hard freeze (28°F) ends
Apr 4
Next 7 nights in Chambersburg

Frost likely Fri night, low 31°F

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

  1. ThuOct 2241°
  2. FriOct 2331°frost
  3. SatOct 2433°possible frost
  4. SunOct 2537°
  5. MonOct 2643°
  6. TueOct 2744°
  7. WedOct 2843°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 18First 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 Chambersburg 1 ESE, 0.9 miles from Chambersburg.

Planting calendar for Chambersburg

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

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesApr 25–May 9
PumpkinsMay 2–May 16
SunflowersApr 18–May 9
CucumbersMay 2–May 9
CornApr 25–May 9
Sweet potatoesMay 9–May 23
WatermelonMay 2–May 16
Green beansApr 25–May 16
ZucchiniApr 25–May 9
OkraMay 9–May 23
PeppersMay 2–May 16
BasilApr 25–May 9
Butternut squashApr 25–May 9
CantaloupeMay 2–May 16
EggplantMay 2–May 16
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesMar 21–Apr 4
OnionsMar 7–Mar 28
CarrotsMar 28–May 2
LettuceApr 4–Apr 25
BroccoliMar 21–Apr 4
BeetsMar 21–May 2
PeasMar 7–Mar 21
CabbageMar 21–Apr 4
RadishesMar 14–Apr 25
Brussels sproutsApr 4–Apr 18
SpinachMar 7–Mar 28
CilantroApr 4–Apr 25
KaleMar 21–Apr 4
Collard greensMar 21–Apr 4
TurnipsMar 21–Apr 4
DillApr 18–May 2
CeleryApr 25–May 2
CauliflowerApr 4–Apr 18
LeeksApr 4–Apr 18
Swiss chardApr 4–May 2
ParsleyApr 4–Apr 25
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsOct 11–Nov 15
GarlicOct 4–Nov 8
Daffodil bulbsSep 27–Nov 8
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 21–Apr 4
AsparagusMar 21–Apr 4

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 3Apr 18May 5Oct 10Oct 25Nov 8
Hard freeze, 28°FMar 21Apr 4Apr 21Oct 23Nov 6Nov 21

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 Chambersburg 1 ESE (USC00361354) sits 0.9 miles from the center of Chambersburg at 640 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 Chambersburg, PA?

The average last frost date in Chambersburg is April 18, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 5.

When is the first frost in Chambersburg?

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 Chambersburg?

About 188 days between the average last and first frost.

When should I plant tomatoes in Chambersburg?

Plant tomato seedlings outside from April 25 to May 9. Start seeds indoors six to eight weeks earlier.

Nearby in Pennsylvania

All 35 cities in Pennsylvania