Last frost date in Norristown, PA
In Norristown, the last spring frost comes around April 8 in an average year. Wait until April 23 if you want 90% odds of no more frost. The first fall frost usually arrives about October 31, which leaves 203 frost-free days. An early freeze before October 14 happens one year in ten.
- Safe after (10% risk)
- Apr 23
- Average first frost
- Oct 31
- Frost-free season
- 203 days
- Hard freeze (28°F) ends
- Mar 31
Frost possible in low spots Fri night, low 34°F
Earlier than usual: the average first frost here is October 31.
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2241°
- FriOct 2334°possible frost
- SatOct 2436°possible frost
- SunOct 2538°
- MonOct 2645°
- TueOct 2745°
- WedOct 2846°
Planting calendar for Norristown
Windows count forward or back from the average frost dates above. Click a crop for dates across Pennsylvania.
TomatoesApr 15–Apr 29
PumpkinsApr 22–May 6
SunflowersApr 8–Apr 29
CucumbersApr 22–Apr 29
CornApr 15–Apr 29
Sweet potatoesApr 29–May 13
WatermelonApr 22–May 6
Green beansApr 15–May 6
ZucchiniApr 15–Apr 29
OkraApr 29–May 13
PeppersApr 22–May 6
BasilApr 15–Apr 29
Butternut squashApr 15–Apr 29
CantaloupeApr 22–May 6
EggplantApr 22–May 6
PotatoesMar 11–Mar 25
OnionsFeb 25–Mar 18
CarrotsMar 18–Apr 22
LettuceMar 25–Apr 15
BroccoliMar 11–Mar 25
BeetsMar 11–Apr 22
PeasFeb 25–Mar 11
CabbageMar 11–Mar 25
RadishesMar 4–Apr 15
Brussels sproutsMar 25–Apr 8
SpinachFeb 25–Mar 18
CilantroMar 25–Apr 15
KaleMar 11–Mar 25
Collard greensMar 11–Mar 25
TurnipsMar 11–Mar 25
DillApr 8–Apr 22
CeleryApr 15–Apr 22
CauliflowerMar 25–Apr 8
LeeksMar 25–Apr 8
Swiss chardMar 25–Apr 22
ParsleyMar 25–Apr 15
Tulip bulbsOct 17–Nov 21
GarlicOct 10–Nov 14
Daffodil bulbsOct 3–Nov 14
StrawberriesMar 11–Mar 25
AsparagusMar 11–Mar 25Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Mar 28 | Apr 8 | Apr 23 | Oct 14 | Oct 31 | Nov 12 |
| Hard freeze, 28°F | Mar 15 | Mar 31 | Apr 12 | Oct 27 | Nov 10 | Nov 22 |
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 Norristown (USC00366370) sits 0.9 miles from the center of Norristown at 62 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 Norristown, PA?
The average last frost date in Norristown is April 8, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 23.
When is the first frost in Norristown?
The first frost in fall usually comes around October 31. One year in ten it arrives before October 14.
How long is the growing season in Norristown?
About 203 days between the average last and first frost.
When should I plant tomatoes in Norristown?
Plant tomato seedlings outside from April 15 to April 29. Start seeds indoors six to eight weeks earlier.
Nearby in Pennsylvania
- King of PrussiaApr 8
- PhoenixvilleApr 18
- Drexel HillApr 2
- PhiladelphiaMar 30
- PottstownApr 20
- ChesterMar 30
- LevittownApr 21
- AllentownApr 20
- ReadingApr 14
- BethlehemApr 20
- EastonApr 18
- LancasterApr 19