Frost dates for 15909Johnstown, PA
The average last spring frost in Johnstown is May 17 and the average first fall frost is October 2, giving a typical growing season of about 136 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 17
- Average first fall frost
- Oct 2
- Growing season
- 136 days
Safer after Jun 1 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 195 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) | May 13 · May 31 · Jun 14 | Sep 5 · Sep 22 · Oct 3 | 112 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 17 · Jun 1 | Sep 19 · Oct 2 · Oct 14 | 136 days | 100% |
| Hard freeze (28°F) | Apr 18 · May 4 · May 22 | Oct 1 · Oct 13 · Oct 30 | 160 days | 100% |
Planting calendar for Johnstown
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 | Apr 16 – Jun 22 |
| Tomatoes | Transplant outdoors | Jun 2 – Jun 12 |
| Peppers | Start seeds indoors | Apr 16 – May 17 |
| Peppers | Transplant outdoors | Jun 16 – Jul 17 |
| Eggplant | Start seeds indoors | May 3 – Jun 1 |
| Eggplant | Transplant outdoors | Jun 16 – Jul 17 |
| Cucumbers | Sow outdoors | Jun 16 – Jun 22 |
| Summer squash | Sow outdoors | Jun 2 – Jul 17 |
| Winter squash & pumpkins | Sow outdoors | Jun 16 – Jul 17 |
| Snap beans | Sow outdoors | Jun 2 – Jul 15 |
| Sweet corn | Sow outdoors | Jun 2 – Jun 12 |
| Watermelon & cantaloupe | Sow outdoors | Jun 16 – Jul 17 |
| Okra | Sow outdoors | Jun 9 – Jul 2 |
| Peas | Sow outdoors (spring) | Apr 16 – Jun 1 |
| Potatoes | Plant outdoors (spring) | Apr 16 – Jun 16 |
| Onions | Start seeds indoors (spring) | Mar 5 – Apr 1 |
| Onions | Transplant outdoors (spring) | May 3 – Jun 1 |
| Broccoli | Start seeds indoors (spring) | Mar 29 – May 2 |
| Broccoli | Transplant outdoors (spring) | May 3 – Jun 1 |
| Broccoli | Start seeds indoors (fall) | Jun 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 19 – Apr 16 |
| Cabbage | Transplant outdoors (spring) | Apr 16 – May 17 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Apr 16 – Jul 2 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Apr 9 – May 23 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Apr 16 – Jun 6 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | May 3 – May 23 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | May 17 – Jul 2 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 15909 is matched to the NOAA station Ebensburg Sewage Plt, PA, 13.5 km away, at 1,940 ft elevation (122 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ebensburg Sewage Plt, PA (used) | 1,940 ft | May 17 | Oct 2 |
| Johnstown Cambria Co Ap, PA | 2,284 ft | Apr 29 | Oct 21 |
| Indiana 3 Se, PA | 1,102 ft | May 8 | Oct 13 |
| Laurel Summit, PA | 2,730 ft | May 6 | Oct 12 |
Frost dates near Johnstown
- Mineral Point, PA 15942 · last Apr 25, first Oct 21
- Parkhill, PA 15945 · last May 17, first Oct 2
- Nanty Glo, PA 15943 · last May 17, first Oct 2
- Johnstown, PA 15906 · last May 8, first Oct 13
- South Fork, PA 15956 · last May 17, first Oct 2
- Twin Rocks, PA 15960 · last May 17, first Oct 2
- Summerhill, PA 15958 · last May 17, first Oct 2
- Vintondale, PA 15961 · last May 17, first Oct 2
Frequently asked questions
- When is the last frost in Johnstown, PA?
- For ZIP code 15909, the average last spring frost (32°F) is May 17, based on NOAA 1991-2020 climate normals for the Ebensburg Sewage Plt, PA weather station. There is a 1-in-10 chance of a frost after June 1.
- When is the first frost in Johnstown, PA?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 15909?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 136 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.