Derry, PA frost dates
How Derry compares
- In 8 years out of 10, the last spring frost in Derry falls between April 18 and May 18, a 30-day window. The first fall frost falls between October 2 and October 27.
- The median last frost is 5 days later than the Pennsylvania median of Apr 27.
- Its 165-day growing season is longer than 30% of the 1,787 Pennsylvania places with a regular frost season (state median 175 days).
- The last frost is 10 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 130 nights a year at or below 32°F.
- Compared with Pittsburgh, PA, 58 km away, the last frost here is 8 days later than there and the growing season is 21 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 18 |
| 50% (median) | May 2 |
| 10% (safe for tender plants) | May 18 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 2 |
| 50% (median) | October 14 |
| 90% (late) | October 27 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Derry, PA
Derry, PA frost dates — last frost May 2, first frost Oct 14, zone 6b. whenisthelastfrost.com
When to plant vegetables in Derry, PA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 7 – Feb 21 | Apr 4 – Apr 18 | — | — |
| Peppers | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Eggplant | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Tomatoes | Mar 7 – Mar 21 | May 9 – May 23 | — | — |
| Lettuce | Mar 7 – Mar 21 | Apr 11 – Apr 25 | Apr 4 – May 9 | Aug 19 – Sep 16 |
| Kale | Mar 7 – Mar 21 | Apr 4 – Apr 18 | Apr 4 – Apr 18 | Aug 5 – Aug 26 |
| Broccoli | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 8 – Jul 29 |
| Cabbage | Mar 7 – Mar 21 | Apr 11 – Apr 25 | — | Jul 8 – Jul 29 |
| Cauliflower | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 8 – Jul 29 |
| Okra | Mar 21 – Apr 4 | May 23 – Jun 6 | May 23 – Jun 6 | — |
| Basil | Mar 21 – Apr 4 | May 9 – May 23 | — | — |
| Peas | — | — | Mar 21 – Apr 11 | Jul 22 – Aug 12 |
| Spinach | — | — | Mar 21 – Apr 11 | Aug 19 – Sep 9 |
| Radishes | — | — | Mar 28 – May 9 | Sep 2 – Sep 23 |
| Cucumbers | Apr 4 – Apr 11 | May 16 – May 23 | May 9 – May 23 | Jul 29 – Aug 12 |
| Zucchini & Summer Squash | Apr 4 – Apr 11 | — | May 9 – May 23 | Aug 5 – Aug 19 |
| Winter Squash & Pumpkins | Apr 4 – Apr 11 | — | May 9 – May 23 | — |
| Melons & Watermelon | Apr 4 – Apr 11 | May 16 – May 30 | — | — |
| Carrots | — | — | Apr 11 – May 9 | Jul 22 – Aug 5 |
| Beets | — | — | Apr 11 – May 9 | Aug 5 – Aug 19 |
| Potatoes | — | — | Apr 11 – May 2 | — |
| Swiss Chard | — | — | Apr 18 – May 16 | Aug 5 – Aug 19 |
| Cilantro | — | — | Apr 18 – May 9 | Aug 19 – Sep 9 |
| Green Beans | — | — | May 9 – May 30 | Jul 29 – Aug 12 |
| Sweet Corn | — | — | May 9 – May 23 | — |
| Sweet Potatoes | — | May 16 – Jun 6 | — | — |
| Garlic | — | — | — | Sep 30 – Nov 4 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Loyalhanna Lake, PA weather station, 17 km away (elevation 991 ft (302 m)).
Frost dates near Derry
- Bradenville May 2 · Oct 14
- New Derry May 2 · Oct 14
- Loyalhanna May 1 · Oct 13
- Youngstown May 1 · Oct 13
- Latrobe May 1 · Oct 13
- Hostetter May 1 · Oct 13
- Southwest May 2 · Oct 14
- New Alexandria May 2 · Oct 14
- Whitney May 1 · Oct 13
- Torrance May 2 · Oct 14
Frequently asked questions
When is the last frost in Derry, PA?
The median last spring frost in Derry, PA is May 2. There is still about a 10% chance of frost after May 18, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Derry, PA?
The median first fall frost is October 14, with about a 10% chance of frost before October 2.
How long is the growing season in Derry, PA?
About 165 days between the median last spring frost and first fall frost.
What planting zone is Derry, PA?
Derry, PA is in USDA hardiness zone 6b.