Choteau 8NE, MT Frost Dates & Growing Season

The two dates every Choteau 8NE garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 20
~50% chance of frost after
First fall frost
Sep 22
~50% chance of frost before
Growing season
125 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 20 Jun 4
First fall frost Oct 4 Sep 22 Sep 8
Hard freeze (28°F), median last May 8 · first Oct 1

Computed from NOAA 1991–2020 climate normals at the CHOTEAU 8NE 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 Choteau 8NE

Computed from Choteau 8NE'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 25 – Apr 8 May 27 – Jun 3
🫑 Peppers Mar 11 – Mar 25 Jun 3 – Jun 10
🥬 Lettuce Apr 8 – Apr 22 Apr 22 – May 6 Apr 22 – May 20
🫛 Peas Apr 8 – Apr 22
🥕 Carrots Apr 29 – May 20
🥦 Broccoli Apr 1 – Apr 15 Apr 29 – May 13
🥬 Kale Apr 8 – Apr 22 Apr 22 – May 6 Apr 22 – May 6
🥒 Cucumbers Apr 22 – Apr 29 May 27 – Jun 3 May 27 – Jun 3
🥒 Zucchini Apr 22 – Apr 29 May 27 – Jun 3 May 27 – Jun 3
🫘 Green Beans (Bush) May 27 – Jun 3
🌽 Sweet Corn May 27 – Jun 3
🌿 Basil Apr 8 – Apr 22 May 27 – Jun 3 Jun 3 – Jun 10
🧄 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 Choteau 8NE's dates automatically after a lookup.

Reading the season in Choteau 8NE

At about 125 frost-free days, Choteau 8NE 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 Choteau 8NE, MT?

The average last spring frost in Choteau 8NE is around May 20, 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 Choteau 8NE, MT?

The average first fall frost in Choteau 8NE 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 Choteau 8NE?

About 125 frost-free days on average, from May 20 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 Choteau 8NE 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.