Harmonsburg, PA frost dates
Last spring frostApr 30median date
First fall frostOct 23median date
Growing season176 daysfrost-free
Hardiness zone6aZone 6a
How Harmonsburg compares
- In 8 years out of 10, the last spring frost in Harmonsburg falls between April 16 and May 17, a 31-day window. The first fall frost falls between October 6 and November 6.
- The median last frost is 3 days later than the Pennsylvania median of Apr 27.
- Its 176-day growing season is longer than 51% of the 1,787 Pennsylvania places with a regular frost season (state median 175 days).
- The last frost is typical for zone 6a, where the median is Apr 29.
- The weather station records an average of 136 nights a year at or below 32°F.
- Compared with Erie, PA, 56 km away, the last frost here is 4 days later than there and the growing season is 16 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 16 |
| 50% (median) | April 30 |
| 10% (safe for tender plants) | May 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 6 |
| 50% (median) | October 23 |
| 90% (late) | November 6 |
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 Harmonsburg, PA
Harmonsburg, PA frost dates — last frost Apr 30, first frost Oct 23, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 5 to Feb 19Transplant outside: Apr 2 to Apr 16
Start indoors: Feb 19 to Mar 5Transplant outside: May 14 to May 28
Start indoors: Feb 19 to Mar 5Transplant outside: May 14 to May 28
Start indoors: Mar 5 to Mar 19Transplant outside: May 7 to May 21
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 9 to Apr 23Sow outdoors: Apr 2 to May 7Plant for fall: Aug 28 to Sep 25
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 2 to Apr 16Sow outdoors: Apr 2 to Apr 16Plant for fall: Aug 14 to Sep 4
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 9 to Apr 23Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 19 to Apr 2Transplant outside: May 21 to Jun 4Sow outdoors: May 21 to Jun 4
Start indoors: Mar 19 to Apr 2Transplant outside: May 7 to May 21
Sow outdoors: Mar 19 to Apr 9Plant for fall: Jul 31 to Aug 21
Sow outdoors: Mar 19 to Apr 9Plant for fall: Aug 28 to Sep 18
Sow outdoors: Mar 26 to May 7Plant for fall: Sep 11 to Oct 2
Start indoors: Apr 2 to Apr 9Transplant outside: May 14 to May 21Sow outdoors: May 7 to May 21Plant for fall: Aug 7 to Aug 21
Start indoors: Apr 2 to Apr 9Sow outdoors: May 7 to May 21Plant for fall: Aug 14 to Aug 28
Start indoors: Apr 2 to Apr 9Sow outdoors: May 7 to May 21
Start indoors: Apr 2 to Apr 9Transplant outside: May 14 to May 28
Sow outdoors: Apr 9 to May 7Plant for fall: Jul 31 to Aug 14
Sow outdoors: Apr 9 to May 7Plant for fall: Aug 14 to Aug 28
Sow outdoors: Apr 9 to Apr 30
Sow outdoors: Apr 16 to May 14Plant for fall: Aug 14 to Aug 28
Sow outdoors: Apr 16 to May 7Plant for fall: Aug 28 to Sep 18
Sow outdoors: May 7 to May 28Plant for fall: Aug 7 to Aug 21
Sow outdoors: May 7 to May 21
Transplant outside: May 14 to Jun 4
Plant for fall: Oct 9 to Nov 13
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Harmonsburg, PA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 5 – Feb 19 | Apr 2 – Apr 16 | — | — |
| Peppers | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Eggplant | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Tomatoes | Mar 5 – Mar 19 | May 7 – May 21 | — | — |
| Lettuce | Mar 5 – Mar 19 | Apr 9 – Apr 23 | Apr 2 – May 7 | Aug 28 – Sep 25 |
| Kale | Mar 5 – Mar 19 | Apr 2 – Apr 16 | Apr 2 – Apr 16 | Aug 14 – Sep 4 |
| Broccoli | Mar 5 – Mar 19 | Apr 16 – Apr 30 | — | Jul 17 – Aug 7 |
| Cabbage | Mar 5 – Mar 19 | Apr 9 – Apr 23 | — | Jul 17 – Aug 7 |
| Cauliflower | Mar 5 – Mar 19 | Apr 16 – Apr 30 | — | Jul 17 – Aug 7 |
| Okra | Mar 19 – Apr 2 | May 21 – Jun 4 | May 21 – Jun 4 | — |
| Basil | Mar 19 – Apr 2 | May 7 – May 21 | — | — |
| Peas | — | — | Mar 19 – Apr 9 | Jul 31 – Aug 21 |
| Spinach | — | — | Mar 19 – Apr 9 | Aug 28 – Sep 18 |
| Radishes | — | — | Mar 26 – May 7 | Sep 11 – Oct 2 |
| Cucumbers | Apr 2 – Apr 9 | May 14 – May 21 | May 7 – May 21 | Aug 7 – Aug 21 |
| Zucchini & Summer Squash | Apr 2 – Apr 9 | — | May 7 – May 21 | Aug 14 – Aug 28 |
| Winter Squash & Pumpkins | Apr 2 – Apr 9 | — | May 7 – May 21 | — |
| Melons & Watermelon | Apr 2 – Apr 9 | May 14 – May 28 | — | — |
| Carrots | — | — | Apr 9 – May 7 | Jul 31 – Aug 14 |
| Beets | — | — | Apr 9 – May 7 | Aug 14 – Aug 28 |
| Potatoes | — | — | Apr 9 – Apr 30 | — |
| Swiss Chard | — | — | Apr 16 – May 14 | Aug 14 – Aug 28 |
| Cilantro | — | — | Apr 16 – May 7 | Aug 28 – Sep 18 |
| Green Beans | — | — | May 7 – May 28 | Aug 7 – Aug 21 |
| Sweet Corn | — | — | May 7 – May 21 | — |
| Sweet Potatoes | — | May 14 – Jun 4 | — | — |
| Garlic | — | — | — | Oct 9 – Nov 13 |
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 Linesville 1 S, PA weather station, 9 km away (elevation 1,030 ft (314 m)).
Frost dates near Harmonsburg
- Conneaut Lake Apr 30 · Oct 23
- Conneautville May 8 · Oct 16
- Linesville Apr 30 · Oct 23
- Hartstown May 4 · Oct 14
- Meadville Apr 30 · Oct 23
- Atlantic Apr 30 · Oct 23
- Saegertown Apr 30 · Oct 23
- Springboro May 8 · Oct 16
- Adamsville May 4 · Oct 14
- Venango Apr 30 · Oct 23
Frequently asked questions
When is the last frost in Harmonsburg, PA?
The median last spring frost in Harmonsburg, PA is April 30. There is still about a 10% chance of frost after May 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Harmonsburg, PA?
The median first fall frost is October 23, with about a 10% chance of frost before October 6.
How long is the growing season in Harmonsburg, PA?
About 176 days between the median last spring frost and first fall frost.
What planting zone is Harmonsburg, PA?
Harmonsburg, PA is in USDA hardiness zone 6a.