Last frost date in North Potomac, MD

Average last frost
April 1

Expect the last frost in North Potomac around April 1. Frost after April 15 happens in only one year out of ten. The first fall frost usually arrives about November 6, which leaves 219 frost-free days. An early freeze before October 24 happens one year in ten.

Safe after (10% risk)
Apr 15
Average first frost
Nov 6
Frost-free season
219 days
Hard freeze (28°F) ends
Mar 22
Next 7 nights in North Potomac

Frost possible in low spots Fri night, low 36°F

Earlier than usual: the average first frost here is November 6.

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

  1. ThuOct 2244°
  2. FriOct 2336°possible frost
  3. SatOct 2437°
  4. SunOct 2538°
  5. MonOct 2644°
  6. TueOct 2746°
  7. WedOct 2847°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 1First frost Nov 6219 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND219 frost-free days
Frost risk through the year at Rockville 1 NE, 4.8 miles from North Potomac.

Planting calendar for North Potomac

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

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 23–Nov 27
GarlicOct 16–Nov 20
Daffodil bulbsOct 9–Nov 20
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 19Apr 1Apr 15Oct 24Nov 6Nov 21
Hard freeze, 28°FMar 5Mar 22Apr 4Nov 5Nov 19Dec 6

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 Rockville 1 NE (USC00187705) sits 4.8 miles from the center of North Potomac at 440 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 North Potomac, MD?

The average last frost date in North Potomac is April 1, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 15.

When is the first frost in North Potomac?

The first frost in fall usually comes around November 6. One year in ten it arrives before October 24.

How long is the growing season in North Potomac?

About 219 days between the average last and first frost.

When should I plant tomatoes in North Potomac?

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

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