Frost dates for 17703 — Williamsport, PA
Last spring frostApr 25median date
First fall frostOct 24median date
Growing season182 daysfrost-free
Hardiness zone6bZone 6b
How Williamsport compares
- In 8 years out of 10, the last spring frost in Williamsport falls between April 10 and May 12, a 32-day window. The first fall frost falls between October 8 and November 5.
- The median last frost is 2 days earlier than the Pennsylvania median of Apr 27.
- Its 182-day growing season is longer than 65% of the 1,787 Pennsylvania places with a regular frost season (state median 175 days).
- The last frost is typical for zone 6b, where the median is Apr 22.
- The weather station records an average of 118 nights a year at or below 32°F.
- Compared with Harrisburg, PA, 108 km away, the last frost here is 10 days later than there and the growing season is 9 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 10 |
| 50% (median) | April 25 |
| 10% (safe for tender plants) | May 12 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 8 |
| 50% (median) | October 24 |
| 90% (late) | November 5 |
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 Williamsport, PA
Frost dates for 17703 — Williamsport, PA — last frost Apr 25, first frost Oct 24, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Jan 31 to Feb 14Transplant outside: Mar 28 to Apr 11
Start indoors: Feb 14 to Feb 28Transplant outside: May 9 to May 23
Start indoors: Feb 14 to Feb 28Transplant outside: May 9 to May 23
Start indoors: Feb 28 to Mar 14Transplant outside: May 2 to May 16
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 4 to Apr 18Sow outdoors: Mar 28 to May 2Plant for fall: Aug 29 to Sep 26
Start indoors: Feb 28 to Mar 14Transplant outside: Mar 28 to Apr 11Sow outdoors: Mar 28 to Apr 11Plant for fall: Aug 15 to Sep 5
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 11 to Apr 25Plant for fall: Jul 18 to Aug 8
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 4 to Apr 18Plant for fall: Jul 18 to Aug 8
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 11 to Apr 25Plant for fall: Jul 18 to Aug 8
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30Sow outdoors: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: May 2 to May 16
Sow outdoors: Mar 14 to Apr 4Plant for fall: Aug 1 to Aug 22
Sow outdoors: Mar 14 to Apr 4Plant for fall: Aug 29 to Sep 19
Sow outdoors: Mar 21 to May 2Plant for fall: Sep 12 to Oct 3
Start indoors: Mar 28 to Apr 4Transplant outside: May 9 to May 16Sow outdoors: May 2 to May 16Plant for fall: Aug 8 to Aug 22
Start indoors: Mar 28 to Apr 4Sow outdoors: May 2 to May 16Plant for fall: Aug 15 to Aug 29
Start indoors: Mar 28 to Apr 4Sow outdoors: May 2 to May 16
Start indoors: Mar 28 to Apr 4Transplant outside: May 9 to May 23
Sow outdoors: Apr 4 to May 2Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 4 to May 2Plant for fall: Aug 15 to Aug 29
Sow outdoors: Apr 4 to Apr 25
Sow outdoors: Apr 11 to May 9Plant for fall: Aug 15 to Aug 29
Sow outdoors: Apr 11 to May 2Plant for fall: Aug 29 to Sep 19
Sow outdoors: May 2 to May 23Plant for fall: Aug 8 to Aug 22
Sow outdoors: May 2 to May 16
Transplant outside: May 9 to May 30
Plant for fall: Oct 10 to Nov 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Williamsport, PA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 31 – Feb 14 | Mar 28 – Apr 11 | — | — |
| Peppers | Feb 14 – Feb 28 | May 9 – May 23 | — | — |
| Eggplant | Feb 14 – Feb 28 | May 9 – May 23 | — | — |
| Tomatoes | Feb 28 – Mar 14 | May 2 – May 16 | — | — |
| Lettuce | Feb 28 – Mar 14 | Apr 4 – Apr 18 | Mar 28 – May 2 | Aug 29 – Sep 26 |
| Kale | Feb 28 – Mar 14 | Mar 28 – Apr 11 | Mar 28 – Apr 11 | Aug 15 – Sep 5 |
| Broccoli | Feb 28 – Mar 14 | Apr 11 – Apr 25 | — | Jul 18 – Aug 8 |
| Cabbage | Feb 28 – Mar 14 | Apr 4 – Apr 18 | — | Jul 18 – Aug 8 |
| Cauliflower | Feb 28 – Mar 14 | Apr 11 – Apr 25 | — | Jul 18 – Aug 8 |
| Okra | Mar 14 – Mar 28 | May 16 – May 30 | May 16 – May 30 | — |
| Basil | Mar 14 – Mar 28 | May 2 – May 16 | — | — |
| Peas | — | — | Mar 14 – Apr 4 | Aug 1 – Aug 22 |
| Spinach | — | — | Mar 14 – Apr 4 | Aug 29 – Sep 19 |
| Radishes | — | — | Mar 21 – May 2 | Sep 12 – Oct 3 |
| Cucumbers | Mar 28 – Apr 4 | May 9 – May 16 | May 2 – May 16 | Aug 8 – Aug 22 |
| Zucchini & Summer Squash | Mar 28 – Apr 4 | — | May 2 – May 16 | Aug 15 – Aug 29 |
| Winter Squash & Pumpkins | Mar 28 – Apr 4 | — | May 2 – May 16 | — |
| Melons & Watermelon | Mar 28 – Apr 4 | May 9 – May 23 | — | — |
| Carrots | — | — | Apr 4 – May 2 | Aug 1 – Aug 15 |
| Beets | — | — | Apr 4 – May 2 | Aug 15 – Aug 29 |
| Potatoes | — | — | Apr 4 – Apr 25 | — |
| Swiss Chard | — | — | Apr 11 – May 9 | Aug 15 – Aug 29 |
| Cilantro | — | — | Apr 11 – May 2 | Aug 29 – Sep 19 |
| Green Beans | — | — | May 2 – May 23 | Aug 8 – Aug 22 |
| Sweet Corn | — | — | May 2 – May 16 | — |
| Sweet Potatoes | — | May 9 – May 30 | — | — |
| Garlic | — | — | — | Oct 10 – Nov 14 |
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 Williamsport, PA weather station, 2 km away (elevation 525 ft (160 m)).
ZIP codes in Williamsport: 17701 17702 17703 17705
Frost dates near Williamsport
- Montoursville Apr 24 · Oct 23
- Cogan Station Apr 25 · Oct 24
- Montgomery Apr 24 · Oct 23
- Linden Apr 25 · Oct 24
- Allenwood Apr 25 · Oct 24
- Dewart Apr 24 · Oct 23
- Antes Fort Apr 30 · Oct 20
- Trout Run Apr 25 · Oct 24
Frequently asked questions
When is the last frost in Williamsport, PA?
The median last spring frost in Williamsport, PA is April 25. There is still about a 10% chance of frost after May 12, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Williamsport, PA?
The median first fall frost is October 24, with about a 10% chance of frost before October 8.
How long is the growing season in Williamsport, PA?
About 182 days between the median last spring frost and first fall frost.
What planting zone is Williamsport, PA?
Williamsport, PA is in USDA hardiness zone 6b.