Grafton, ND Frost Dates & Growing Season

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

Last spring frost
May 4
~50% chance of frost after
First fall frost
Oct 7
~50% chance of frost before
Growing season
156 days
frost-free stretch
USDA zone
≈ 4a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 19 May 4 May 18
First fall frost Oct 21 Oct 7 Sep 25
Hard freeze (28°F), median last Apr 24 · first Oct 17

Computed from NOAA 1991–2020 climate normals at the GRAFTON 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 Grafton

Computed from Grafton'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 9 – Mar 23 May 11 – May 18
🫑 Peppers Feb 23 – Mar 9 May 18 – May 25
🥬 Lettuce Mar 23 – Apr 6 Apr 6 – Apr 20 Apr 6 – May 4
🫛 Peas Mar 23 – Apr 6
🥕 Carrots Apr 13 – May 4
🥦 Broccoli Mar 16 – Mar 30 Apr 13 – Apr 27
🥬 Kale Mar 23 – Apr 6 Apr 6 – Apr 20 Apr 6 – Apr 20
🥒 Cucumbers Apr 6 – Apr 13 May 11 – May 18 May 11 – May 18
🥒 Zucchini Apr 6 – Apr 13 May 11 – May 18 May 11 – May 18
🫘 Green Beans (Bush) May 11 – May 18
🌽 Sweet Corn May 11 – May 18
🌿 Basil Mar 23 – Apr 6 May 11 – May 18 May 18 – May 25
🧄 Garlic Fall: Aug 26 – Sep 23

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 Grafton's dates automatically after a lookup.

Reading the season in Grafton

Roughly 156 frost-free days gives Grafton gardeners room for nearly every common vegetable. Warm-season crops go out after May 4; a fall garden sown in late summer matures comfortably before the Oct 7 frost.

Frequently asked questions

When is the last frost in Grafton, ND?

The average last spring frost in Grafton is around May 4, 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 Grafton, ND?

The average first fall frost in Grafton arrives around Oct 7. 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 Grafton?

About 156 frost-free days on average, from May 4 to Oct 7. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Grafton in?

USDA zone 4a 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.