Frost dates for 15231Pittsburgh, PA
The average last spring frost in Pittsburgh is April 23 and the average first fall frost is October 23, giving a typical growing season of about 181 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 23
- Average first fall frost
- Oct 23
- Growing season
- 181 days
Safer after May 12 (1-in-10 risk)
Possible by Oct 9 (1-in-10 risk)
Last frost typically in 171 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 19 · May 4 · May 22 | Sep 30 · Oct 12 · Oct 25 | 159 days | 100% |
| Frost / freeze (32°F) | Apr 9 · Apr 23 · May 12 | Oct 9 · Oct 23 · Nov 6 | 181 days | 100% |
| Hard freeze (28°F) | Mar 28 · Apr 12 · Apr 27 | Oct 21 · Nov 4 · Nov 18 | 207 days | 100% |
Planting calendar for Pittsburgh
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 23 – May 29 |
| Tomatoes | Transplant outdoors | May 9 – Jul 3 |
| Peppers | Start seeds indoors | Mar 23 – Apr 23 |
| Peppers | Transplant outdoors | May 23 – Jun 23 |
| Eggplant | Start seeds indoors | Apr 9 – May 8 |
| Eggplant | Transplant outdoors | May 23 – Jun 23 |
| Cucumbers | Sow outdoors | May 23 – Jul 13 |
| Summer squash | Sow outdoors | May 9 – Jun 23 |
| Winter squash & pumpkins | Sow outdoors | May 23 – Jun 23 |
| Snap beans | Sow outdoors | May 9 – Aug 5 |
| Sweet corn | Sow outdoors | May 9 – Jul 3 |
| Watermelon & cantaloupe | Sow outdoors | May 23 – Jun 23 |
| Okra | Sow outdoors | May 16 – Jun 8 |
| Peas | Sow outdoors (spring) | Mar 23 – May 8 |
| Potatoes | Plant outdoors (spring) | Mar 23 – May 23 |
| Onions | Start seeds indoors (spring) | Feb 9 – Mar 8 |
| Onions | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (spring) | Mar 5 – Apr 8 |
| Broccoli | Transplant outdoors (spring) | Apr 9 – May 8 |
| Broccoli | Start seeds indoors (fall) | Jun 23 – Jul 3 |
| Broccoli | Transplant outdoors (fall) | Jul 23 – Aug 3 |
| Cabbage | Start seeds indoors (spring) | Feb 23 – Mar 23 |
| Cabbage | Transplant outdoors (spring) | Mar 23 – Apr 23 |
| Cabbage | Start seeds indoors (fall) | Jun 13 – Jul 13 |
| Cabbage | Transplant outdoors (fall) | Jul 13 – Aug 13 |
| Leaf lettuce | Sow outdoors (spring) | Mar 23 – Jun 8 |
| Leaf lettuce | Sow outdoors (fall) | Jul 13 – Aug 29 |
| Spinach | Sow outdoors (spring) | Mar 16 – Apr 29 |
| Spinach | Sow outdoors (fall) | Jul 30 – Sep 3 |
| Radishes | Sow outdoors (spring) | Mar 23 – May 13 |
| Radishes | Sow outdoors (fall) | Jul 13 – Sep 13 |
| Kale | Sow outdoors (spring) | Apr 9 – Apr 29 |
| Kale | Sow outdoors (fall) | Jul 6 – Aug 13 |
| Carrots | Sow outdoors (spring) | Apr 23 – Jun 8 |
| Carrots | Sow outdoors (fall) | Jun 13 – Jul 29 |
| Garlic | Plant outdoors (fall) | Oct 13 – Nov 13 |
Where these dates come from
ZIP code 15231 is matched to the NOAA station Pittsburgh Intl Ap, PA, 3 km away, at 1,203 ft elevation (48 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Pittsburgh Intl Ap, PA (used) | 1,203 ft | Apr 23 | Oct 23 |
| Moon Twp, PA | 1,172 ft | Apr 28 | Oct 18 |
| Glenwillard Dashields L&D, PA | 710 ft | Apr 8 | Nov 8 |
| Emsworth L/D Ohio Rvr, PA | 717 ft | Apr 24 | Oct 27 |
Frost dates near Pittsburgh
- Coraopolis, PA 15108 · last Apr 23, first Oct 23
- Imperial, PA 15126 · last Apr 23, first Oct 23
- Crescent, PA 15046 · last Apr 23, first Oct 23
- Pittsburgh, PA 15275 · last Apr 23, first Oct 23
- Clinton, PA 15026 · last Apr 23, first Oct 23
- Leetsdale, PA 15056 · last Apr 24, first Oct 27
- South Heights, PA 15081 · last Apr 23, first Oct 23
- Sewickley, PA 15143 · last Apr 23, first Oct 23
Frequently asked questions
- When is the last frost in Pittsburgh, PA?
- For ZIP code 15231, the average last spring frost (32°F) is April 23, based on NOAA 1991-2020 climate normals for the Pittsburgh Intl Ap, PA weather station. There is a 1-in-10 chance of a frost after May 12.
- When is the first frost in Pittsburgh, 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 15231?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 181 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.