Errol Airport, NH Frost Dates & Growing Season

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

Last spring frost
May 21
~50% chance of frost after
First fall frost
Sep 22
~50% chance of frost before
Growing season
124 days
frost-free stretch
USDA zone
≈ 4b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 7 May 21 Jun 3
First fall frost Oct 4 Sep 22 Sep 9
Hard freeze (28°F), median last May 8 · first Oct 2

Computed from NOAA 1991–2020 climate normals at the ERROL AP station. "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 Errol Airport

Computed from Errol Airport's own frost dates. Click any crop for the full zone-4 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Mar 26 – Apr 9 May 28 – Jun 4
🫑 Peppers Mar 12 – Mar 26 Jun 4 – Jun 11
🥬 Lettuce Apr 9 – Apr 23 Apr 23 – May 7 Apr 23 – May 21
🫛 Peas Apr 9 – Apr 23
🥕 Carrots Apr 30 – May 21
🥦 Broccoli Apr 2 – Apr 16 Apr 30 – May 14
🥬 Kale Apr 9 – Apr 23 Apr 23 – May 7 Apr 23 – May 7
🥒 Cucumbers Apr 23 – Apr 30 May 28 – Jun 4 May 28 – Jun 4
🥒 Zucchini Apr 23 – Apr 30 May 28 – Jun 4 May 28 – Jun 4
🫘 Green Beans (Bush) May 28 – Jun 4
🌽 Sweet Corn May 28 – Jun 4
🌿 Basil Apr 9 – Apr 23 May 28 – Jun 4 Jun 4 – Jun 11
🧄 Garlic Fall: Aug 11 – Sep 8

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 Errol Airport's dates automatically after a lookup.

Reading the season in Errol Airport

At about 124 frost-free days, Errol Airport rewards efficiency: start warm-season crops indoors, favor short-season varieties, and lean on cold-tolerant crops — peas, kale, roots — that shrug off the shoulder-season frosts on either end.

Frequently asked questions

When is the last frost in Errol Airport, NH?

The average last spring frost in Errol Airport is around May 21, 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 Errol Airport, NH?

The average first fall frost in Errol Airport arrives around Sep 22. 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 Errol Airport?

About 124 frost-free days on average, from May 21 to Sep 22. That favors short-season varieties and transplants for warm-season crops, with cool-season vegetables doing the heavy lifting in spring and fall.

What USDA zone is Errol Airport in?

USDA zone 4b 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.