Frost dates for 19512Boyertown, PA
The average last spring frost in Boyertown is April 20 and the average first fall frost is October 23, giving a typical growing season of about 186 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 20
- Average first fall frost
- Oct 23
- Growing season
- 186 days
Safer after May 6 (1-in-10 risk)
Possible by Oct 9 (1-in-10 risk)
Last frost typically in 168 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 18 · May 2 · May 19 | Oct 1 · Oct 12 · Oct 26 | 162 days | 100% |
| Frost / freeze (32°F) | Apr 5 · Apr 20 · May 6 | Oct 9 · Oct 23 · Nov 5 | 186 days | 100% |
| Hard freeze (28°F) | Mar 23 · Apr 6 · Apr 21 | Oct 19 · Nov 3 · Nov 18 | 212 days | 100% |
Planting calendar for Boyertown
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 20 – May 26 |
| Tomatoes | Transplant outdoors | May 6 – Jul 3 |
| Peppers | Start seeds indoors | Mar 20 – Apr 20 |
| Peppers | Transplant outdoors | May 20 – Jun 20 |
| Eggplant | Start seeds indoors | Apr 6 – May 5 |
| Eggplant | Transplant outdoors | May 20 – Jun 20 |
| Cucumbers | Sow outdoors | May 20 – Jul 13 |
| Summer squash | Sow outdoors | May 6 – Jun 20 |
| Winter squash & pumpkins | Sow outdoors | May 20 – Jun 20 |
| Snap beans | Sow outdoors | May 6 – Aug 5 |
| Sweet corn | Sow outdoors | May 6 – Jul 3 |
| Watermelon & cantaloupe | Sow outdoors | May 20 – Jun 20 |
| Okra | Sow outdoors | May 13 – Jun 5 |
| Peas | Sow outdoors (spring) | Mar 20 – May 5 |
| Potatoes | Plant outdoors (spring) | Mar 20 – May 20 |
| Onions | Start seeds indoors (spring) | Feb 6 – Mar 5 |
| Onions | Transplant outdoors (spring) | Apr 6 – May 5 |
| Broccoli | Start seeds indoors (spring) | Mar 2 – Apr 5 |
| Broccoli | Transplant outdoors (spring) | Apr 6 – May 5 |
| Broccoli | Start seeds indoors (fall) | Jun 23 – Jul 3 |
| Broccoli | Transplant outdoors (fall) | Jul 23 – Aug 3 |
| Cabbage | Start seeds indoors (spring) | Feb 20 – Mar 20 |
| Cabbage | Transplant outdoors (spring) | Mar 20 – Apr 20 |
| Cabbage | Start seeds indoors (fall) | Jun 13 – Jul 13 |
| Cabbage | Transplant outdoors (fall) | Jul 13 – Aug 13 |
| Leaf lettuce | Sow outdoors (spring) | Mar 20 – Jun 5 |
| Leaf lettuce | Sow outdoors (fall) | Jul 13 – Aug 29 |
| Spinach | Sow outdoors (spring) | Mar 13 – Apr 26 |
| Spinach | Sow outdoors (fall) | Jul 30 – Sep 3 |
| Radishes | Sow outdoors (spring) | Mar 20 – May 10 |
| Radishes | Sow outdoors (fall) | Jul 13 – Sep 13 |
| Kale | Sow outdoors (spring) | Apr 6 – Apr 26 |
| Kale | Sow outdoors (fall) | Jul 6 – Aug 13 |
| Carrots | Sow outdoors (spring) | Apr 20 – Jun 5 |
| Carrots | Sow outdoors (fall) | Jun 13 – Jul 29 |
| Garlic | Plant outdoors (fall) | Oct 13 – Nov 13 |
Where these dates come from
ZIP code 19512 is matched to the NOAA station Pottstown Limerick Ap, PA, 13.8 km away, at 291 ft elevation (136 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Pottstown Limerick Ap, PA (used) | 291 ft | Apr 20 | Oct 23 |
| Graterford 1 E, PA | 279 ft | Apr 24 | Oct 15 |
| Rodale Rsch Ctr, PA | 550 ft | Apr 26 | Oct 14 |
| Reading 4 Nnw, PA | 360 ft | Apr 10 | Oct 31 |
Frost dates near Boyertown
- New Berlinville, PA 19545 · last Apr 20, first Oct 23
- Bechtelsville, PA 19505 · last Apr 20, first Oct 23
- Pine Forge, PA 19548 · last Apr 20, first Oct 23
- Gilbertsville, PA 19525 · last Apr 20, first Oct 23
- Earlville, PA 19519 · last Apr 20, first Oct 23
- Sassamansville, PA 19472 · last Apr 20, first Oct 23
- Frederick, PA 19435 · last Apr 20, first Oct 23
- Pottstown, PA 19464 · last Apr 20, first Oct 23
Frequently asked questions
- When is the last frost in Boyertown, PA?
- For ZIP code 19512, the average last spring frost (32°F) is April 20, based on NOAA 1991-2020 climate normals for the Pottstown Limerick Ap, PA weather station. There is a 1-in-10 chance of a frost after May 6.
- When is the first frost in Boyertown, PA?
- The average first fall frost (32°F) is October 23. There is a 1-in-10 chance of frost by October 9, so tender plants are at risk from that point on.
- How long is the growing season in 19512?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 186 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.