Frost dates for 17121 — Harrisburg, PA
Last spring frostApr 15median date
First fall frostOct 23median date
Growing season191 daysfrost-free
Hardiness zone7aZone 7a
How Harrisburg compares
- In 8 years out of 10, the last spring frost in Harrisburg falls between April 1 and May 2, a 31-day window. The first fall frost falls between October 7 and November 7.
- The median last frost is 12 days earlier than the Pennsylvania median of Apr 27.
- Its 191-day growing season is longer than 81% of the 1,787 Pennsylvania places with a regular frost season (state median 175 days).
- The last frost is typical for zone 7a, where the median is Apr 16.
- The weather station records an average of 111 nights a year at or below 32°F.
- Compared with Lancaster, PA, 57 km away, the last frost here is 4 days earlier than there and the growing season is 3 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 1 |
| 50% (median) | April 15 |
| 10% (safe for tender plants) | May 2 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 7 |
| 50% (median) | October 23 |
| 90% (late) | November 7 |
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 Harrisburg, PA
Frost dates for 17121 — Harrisburg, PA — last frost Apr 15, first frost Oct 23, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Jan 21 to Feb 4Transplant outside: Mar 18 to Apr 1
Start indoors: Feb 4 to Feb 18Transplant outside: Apr 29 to May 13
Start indoors: Feb 4 to Feb 18Transplant outside: Apr 29 to May 13
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 22 to May 6
Start indoors: Feb 18 to Mar 4Transplant outside: Mar 25 to Apr 8Sow outdoors: Mar 18 to Apr 22Plant for fall: Aug 28 to Sep 25
Start indoors: Feb 18 to Mar 4Transplant outside: Mar 18 to Apr 1Sow outdoors: Mar 18 to Apr 1Plant for fall: Aug 14 to Sep 4
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 1 to Apr 15Plant for fall: Jul 17 to Aug 7
Start indoors: Feb 18 to Mar 4Transplant outside: Mar 25 to Apr 8Plant for fall: Jul 17 to Aug 7
Start indoors: Feb 18 to Mar 4Transplant outside: Apr 1 to Apr 15Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 4 to Mar 18Transplant outside: May 6 to May 20Sow outdoors: May 6 to May 20
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 22 to May 6
Sow outdoors: Mar 4 to Mar 25Plant for fall: Jul 31 to Aug 21
Sow outdoors: Mar 4 to Mar 25Plant for fall: Aug 28 to Sep 18
Sow outdoors: Mar 11 to Apr 22Plant for fall: Sep 11 to Oct 2
Start indoors: Mar 18 to Mar 25Transplant outside: Apr 29 to May 6Sow outdoors: Apr 22 to May 6Plant for fall: Aug 7 to Aug 21
Start indoors: Mar 18 to Mar 25Sow outdoors: Apr 22 to May 6Plant for fall: Aug 14 to Aug 28
Start indoors: Mar 18 to Mar 25Sow outdoors: Apr 22 to May 6
Start indoors: Mar 18 to Mar 25Transplant outside: Apr 29 to May 13
Sow outdoors: Mar 25 to Apr 22Plant for fall: Jul 31 to Aug 14
Sow outdoors: Mar 25 to Apr 22Plant for fall: Aug 14 to Aug 28
Sow outdoors: Mar 25 to Apr 15
Sow outdoors: Apr 1 to Apr 29Plant for fall: Aug 14 to Aug 28
Sow outdoors: Apr 1 to Apr 22Plant for fall: Aug 28 to Sep 18
Sow outdoors: Apr 22 to May 13Plant for fall: Aug 7 to Aug 21
Sow outdoors: Apr 22 to May 6
Transplant outside: Apr 29 to May 20
Plant for fall: Oct 9 to Nov 13
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Harrisburg, PA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 21 – Feb 4 | Mar 18 – Apr 1 | — | — |
| Peppers | Feb 4 – Feb 18 | Apr 29 – May 13 | — | — |
| Eggplant | Feb 4 – Feb 18 | Apr 29 – May 13 | — | — |
| Tomatoes | Feb 18 – Mar 4 | Apr 22 – May 6 | — | — |
| Lettuce | Feb 18 – Mar 4 | Mar 25 – Apr 8 | Mar 18 – Apr 22 | Aug 28 – Sep 25 |
| Kale | Feb 18 – Mar 4 | Mar 18 – Apr 1 | Mar 18 – Apr 1 | Aug 14 – Sep 4 |
| Broccoli | Feb 18 – Mar 4 | Apr 1 – Apr 15 | — | Jul 17 – Aug 7 |
| Cabbage | Feb 18 – Mar 4 | Mar 25 – Apr 8 | — | Jul 17 – Aug 7 |
| Cauliflower | Feb 18 – Mar 4 | Apr 1 – Apr 15 | — | Jul 17 – Aug 7 |
| Okra | Mar 4 – Mar 18 | May 6 – May 20 | May 6 – May 20 | — |
| Basil | Mar 4 – Mar 18 | Apr 22 – May 6 | — | — |
| Peas | — | — | Mar 4 – Mar 25 | Jul 31 – Aug 21 |
| Spinach | — | — | Mar 4 – Mar 25 | Aug 28 – Sep 18 |
| Radishes | — | — | Mar 11 – Apr 22 | Sep 11 – Oct 2 |
| Cucumbers | Mar 18 – Mar 25 | Apr 29 – May 6 | Apr 22 – May 6 | Aug 7 – Aug 21 |
| Zucchini & Summer Squash | Mar 18 – Mar 25 | — | Apr 22 – May 6 | Aug 14 – Aug 28 |
| Winter Squash & Pumpkins | Mar 18 – Mar 25 | — | Apr 22 – May 6 | — |
| Melons & Watermelon | Mar 18 – Mar 25 | Apr 29 – May 13 | — | — |
| Carrots | — | — | Mar 25 – Apr 22 | Jul 31 – Aug 14 |
| Beets | — | — | Mar 25 – Apr 22 | Aug 14 – Aug 28 |
| Potatoes | — | — | Mar 25 – Apr 15 | — |
| Swiss Chard | — | — | Apr 1 – Apr 29 | Aug 14 – Aug 28 |
| Cilantro | — | — | Apr 1 – Apr 22 | Aug 28 – Sep 18 |
| Green Beans | — | — | Apr 22 – May 13 | Aug 7 – Aug 21 |
| Sweet Corn | — | — | Apr 22 – May 6 | — |
| Sweet Potatoes | — | Apr 29 – May 20 | — | — |
| 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 Harrisburg 1 Ne, PA weather station, 2 km away (elevation 420 ft (128 m)).
ZIP codes in Harrisburg: 17101 17102 17103 17104 17105 17106 17107 17108 17109 17110 17111 17112 17113 17120 17121 17122 17123 17124 17125 17126 17127 17128 17129 17130 17140 17177
Frost dates near Harrisburg
- Summerdale Apr 15 · Oct 23
- Enola Apr 15 · Oct 23
- Lemoyne Apr 15 · Oct 23
- Camp Hill Apr 15 · Oct 23
- Marysville Apr 15 · Oct 23
- New Cumberland Apr 9 · Nov 1
- Dauphin Apr 15 · Oct 23
- Highspire Apr 9 · Nov 2
Frequently asked questions
When is the last frost in Harrisburg, PA?
The median last spring frost in Harrisburg, PA is April 15. There is still about a 10% chance of frost after May 2, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Harrisburg, PA?
The median first fall frost is October 23, with about a 10% chance of frost before October 7.
How long is the growing season in Harrisburg, PA?
About 191 days between the median last spring frost and first fall frost.
What planting zone is Harrisburg, PA?
Harrisburg, PA is in USDA hardiness zone 7a.