Frost dates for 15424Confluence, PA
The average last spring frost in Confluence is April 30 and the average first fall frost is October 18, giving a typical growing season of about 171 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 30
- Average first fall frost
- Oct 18
- Growing season
- 171 days
Safer after May 18 (1-in-10 risk)
Possible by Oct 4 (1-in-10 risk)
Last frost typically in 178 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 27 · May 11 · May 28 | Sep 23 · Oct 7 · Oct 22 | 149 days | 100% |
| Frost / freeze (32°F) | Apr 17 · Apr 30 · May 18 | Oct 4 · Oct 18 · Oct 31 | 171 days | 100% |
| Hard freeze (28°F) | Apr 2 · Apr 18 · May 2 | Oct 14 · Oct 29 · Nov 10 | 192 days | 100% |
Planting calendar for Confluence
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 30 – Jun 5 |
| Tomatoes | Transplant outdoors | May 16 – Jun 28 |
| Peppers | Start seeds indoors | Mar 30 – Apr 30 |
| Peppers | Transplant outdoors | May 30 – Jun 30 |
| Eggplant | Start seeds indoors | Apr 16 – May 15 |
| Eggplant | Transplant outdoors | May 30 – Jun 30 |
| Cucumbers | Sow outdoors | May 30 – Jul 8 |
| Summer squash | Sow outdoors | May 16 – Jun 30 |
| Winter squash & pumpkins | Sow outdoors | May 30 – Jun 30 |
| Snap beans | Sow outdoors | May 16 – Jul 31 |
| Sweet corn | Sow outdoors | May 16 – Jun 28 |
| Watermelon & cantaloupe | Sow outdoors | May 30 – Jun 30 |
| Okra | Sow outdoors | May 23 – Jun 15 |
| Peas | Sow outdoors (spring) | Mar 30 – May 15 |
| Potatoes | Plant outdoors (spring) | Mar 30 – May 30 |
| Onions | Start seeds indoors (spring) | Feb 16 – Mar 15 |
| Onions | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (spring) | Mar 12 – Apr 15 |
| Broccoli | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (fall) | Jun 18 – Jun 28 |
| Broccoli | Transplant outdoors (fall) | Jul 18 – Jul 29 |
| Cabbage | Start seeds indoors (spring) | Mar 2 – Mar 30 |
| Cabbage | Transplant outdoors (spring) | Mar 30 – Apr 30 |
| Cabbage | Start seeds indoors (fall) | Jun 8 – Jul 8 |
| Cabbage | Transplant outdoors (fall) | Jul 8 – Aug 8 |
| Leaf lettuce | Sow outdoors (spring) | Mar 30 – Jun 15 |
| Leaf lettuce | Sow outdoors (fall) | Jul 8 – Aug 24 |
| Spinach | Sow outdoors (spring) | Mar 23 – May 6 |
| Spinach | Sow outdoors (fall) | Jul 25 – Aug 29 |
| Radishes | Sow outdoors (spring) | Mar 30 – May 20 |
| Radishes | Sow outdoors (fall) | Jul 8 – Sep 8 |
| Kale | Sow outdoors (spring) | Apr 16 – May 6 |
| Kale | Sow outdoors (fall) | Jul 1 – Aug 8 |
| Carrots | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Carrots | Sow outdoors (fall) | Jun 8 – Jul 24 |
| Garlic | Plant outdoors (fall) | Oct 8 – Nov 8 |
Where these dates come from
ZIP code 15424 is matched to the NOAA station Confluence 1 Sw Dam, PA, 1.7 km away, at 1,490 ft elevation (158 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Confluence 1 Sw Dam, PA (used) | 1,490 ft | Apr 30 | Oct 18 |
| Chalk Hill 2 Ene, PA | 1,980 ft | May 19 | Oct 1 |
| Hidden Valley, PA | 2,876 ft | May 2 | Oct 17 |
| Meyersdale 2 Ssw, PA | 2,000 ft | May 12 | Oct 5 |
Frost dates near Confluence
- Ursina, PA 15485 · last Apr 30, first Oct 18
- Addison, PA 15411 · last May 19, first Oct 1
- Markleton, PA 15551 · last Apr 30, first Oct 18
- Fort Hill, PA 15540 · last May 12, first Oct 5
- Markleysburg, PA 15459 · last May 19, first Oct 1
- Ohiopyle, PA 15470 · last Apr 30, first Oct 18
- Friendsville, MD 21531 · last Apr 30, first Oct 18
- Farmington, PA 15437 · last May 19, first Oct 1
Frequently asked questions
- When is the last frost in Confluence, PA?
- For ZIP code 15424, the average last spring frost (32°F) is April 30, based on NOAA 1991-2020 climate normals for the Confluence 1 Sw Dam, PA weather station. There is a 1-in-10 chance of a frost after May 18.
- When is the first frost in Confluence, PA?
- The average first fall frost (32°F) is October 18. There is a 1-in-10 chance of frost by October 4, so tender plants are at risk from that point on.
- How long is the growing season in 15424?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 171 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.