Harrisburg, PA Frost Dates & Growing Season

The two dates every Harrisburg garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Apr 15
~50% chance of frost after
First fall frost
Oct 23
~50% chance of frost before
Growing season
191 days
frost-free stretch
USDA zone
7a
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 1 Apr 15 May 2
First fall frost Nov 7 Oct 23 Oct 7
Hard freeze (28°F), median last Apr 3 · first Nov 5

Computed from NOAA 1991–2020 climate normals at the Harrisburg 1 NE station (2 km from central Harrisburg). "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Harrisburg

Computed from Harrisburg's own frost dates. Click any crop for the full zone-7 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 18 – Mar 4 Apr 22 – Apr 29
🫑 Peppers Feb 4 – Feb 18 Apr 29 – May 6
🥬 Lettuce Mar 4 – Mar 18 Mar 18 – Apr 1 Mar 18 – Apr 15
🫛 Peas Mar 4 – Mar 18
🥕 Carrots Mar 25 – Apr 15
🥦 Broccoli Feb 25 – Mar 11 Mar 25 – Apr 8
🥬 Kale Mar 4 – Mar 18 Mar 18 – Apr 1 Mar 18 – Apr 1
🥒 Cucumbers Mar 18 – Mar 25 Apr 22 – Apr 29 Apr 22 – Apr 29
🥒 Zucchini Mar 18 – Mar 25 Apr 22 – Apr 29 Apr 22 – Apr 29
🫘 Green Beans (Bush) Apr 22 – Apr 29
🌽 Sweet Corn Apr 22 – Apr 29
🌿 Basil Mar 4 – Mar 18 Apr 22 – Apr 29 Apr 29 – May 6
🧄 Garlic Fall: Sep 11 – Oct 9

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Harrisburg's dates automatically after a lookup.

Reading the season in Harrisburg

Roughly 191 frost-free days gives Harrisburg gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 15; a fall garden sown in late summer matures comfortably before the Oct 23 frost.

Frequently asked questions

When is the last frost in Harrisburg, PA?

The average last spring frost in Harrisburg is around Apr 15, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Harrisburg, PA?

The average first fall frost in Harrisburg arrives around Oct 23. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Harrisburg?

About 191 frost-free days on average, from Apr 15 to Oct 23. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Harrisburg in?

USDA zone 7a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.