Frost dates for 16601Altoona, PA
The average last spring frost in Altoona is April 25 and the average first fall frost is October 21, giving a typical growing season of about 176 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 25
- Average first fall frost
- Oct 21
- Growing season
- 176 days
Safer after May 11 (1-in-10 risk)
Possible by Oct 5 (1-in-10 risk)
Last frost typically in 173 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 21 · May 4 · May 22 | Sep 26 · Oct 8 · Oct 21 | 155 days | 100% |
| Frost / freeze (32°F) | Apr 10 · Apr 25 · May 11 | Oct 5 · Oct 21 · Nov 5 | 176 days | 100% |
| Hard freeze (28°F) | Apr 1 · Apr 13 · May 1 | Oct 19 · Nov 3 · Nov 17 | 202 days | 100% |
Planting calendar for Altoona
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 25 – May 31 |
| Tomatoes | Transplant outdoors | May 11 – Jul 1 |
| Peppers | Start seeds indoors | Mar 25 – Apr 25 |
| Peppers | Transplant outdoors | May 25 – Jun 25 |
| Eggplant | Start seeds indoors | Apr 11 – May 10 |
| Eggplant | Transplant outdoors | May 25 – Jun 25 |
| Cucumbers | Sow outdoors | May 25 – Jul 11 |
| Summer squash | Sow outdoors | May 11 – Jun 25 |
| Winter squash & pumpkins | Sow outdoors | May 25 – Jun 25 |
| Snap beans | Sow outdoors | May 11 – Aug 3 |
| Sweet corn | Sow outdoors | May 11 – Jul 1 |
| Watermelon & cantaloupe | Sow outdoors | May 25 – Jun 25 |
| Okra | Sow outdoors | May 18 – Jun 10 |
| Peas | Sow outdoors (spring) | Mar 25 – May 10 |
| Potatoes | Plant outdoors (spring) | Mar 25 – May 25 |
| Onions | Start seeds indoors (spring) | Feb 11 – Mar 10 |
| Onions | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (spring) | Mar 7 – Apr 10 |
| Broccoli | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (fall) | Jun 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 25 – Mar 25 |
| Cabbage | Transplant outdoors (spring) | Mar 25 – Apr 25 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 25 – Jun 10 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 18 – May 1 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 25 – May 15 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 11 – May 1 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 16601 is matched to the NOAA station Altoona 3 W, PA, 5.7 km away, at 1,320 ft elevation (9 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Altoona 3 W, PA (used) | 1,320 ft | Apr 25 | Oct 21 |
| Altoona 7 Sw, PA | 1,180 ft | Apr 25 | Oct 20 |
| Prince Gallitzin Sp, PA | 1,520 ft | May 10 | Oct 5 |
| Altoona Blair Co Ap, PA | 1,480 ft | Apr 23 | Oct 21 |
Frost dates near Altoona
- Altoona, PA 16603 · last Apr 25, first Oct 20
- Hollidaysburg, PA 16648 · last Apr 25, first Oct 20
- Coupon, PA 16629 · last May 17, first Oct 2
- Duncansville, PA 16635 · last Apr 25, first Oct 20
- Bellwood, PA 16617 · last Apr 25, first Oct 20
- Ashville, PA 16613 · last May 17, first Oct 2
- Gallitzin, PA 16641 · last May 17, first Oct 2
- Dysart, PA 16636 · last May 10, first Oct 5
Frequently asked questions
- When is the last frost in Altoona, PA?
- For ZIP code 16601, the average last spring frost (32°F) is April 25, based on NOAA 1991-2020 climate normals for the Altoona 3 W, PA weather station. There is a 1-in-10 chance of a frost after May 11.
- When is the first frost in Altoona, PA?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 5, so tender plants are at risk from that point on.
- How long is the growing season in 16601?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 176 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.