Divide, MT Frost Dates & Growing Season

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

Last spring frost
Jun 10
~50% chance of frost after
First fall frost
Sep 7
~50% chance of frost before
Growing season
89 days
frost-free stretch
USDA zone
≈ 5b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 23 Jun 10 Jul 2
First fall frost Sep 20 Sep 7 Aug 24
Hard freeze (28°F), median last May 21 · first Sep 19

Computed from NOAA 1991–2020 climate normals at the DIVIDE 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 Divide

Computed from Divide's own frost dates. Click any crop for the full zone-5 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Apr 15 – Apr 29 Jun 17 – Jun 24
🫑 Peppers Apr 1 – Apr 15 Jun 24 – Jul 1
🥬 Lettuce Apr 29 – May 13 May 13 – May 27 May 13 – Jun 10
🫛 Peas Apr 29 – May 13
🥕 Carrots May 20 – Jun 10
🥦 Broccoli Apr 22 – May 6 May 20 – Jun 3
🥬 Kale Apr 29 – May 13 May 13 – May 27 May 13 – May 27
🥒 Cucumbers May 13 – May 20 Jun 17 – Jun 24 Jun 17 – Jun 24
🥒 Zucchini May 13 – May 20 Jun 17 – Jun 24 Jun 17 – Jun 24
🫘 Green Beans (Bush) Jun 17 – Jun 24
🌽 Sweet Corn Jun 17 – Jun 24
🌿 Basil Apr 29 – May 13 Jun 17 – Jun 24 Jun 24 – Jul 1
🧄 Garlic Fall: Jul 27 – Aug 24

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 Divide's dates automatically after a lookup.

Reading the season in Divide

At about 89 frost-free days, Divide 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 Divide, MT?

The average last spring frost in Divide is around Jun 10, 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 Divide, MT?

The average first fall frost in Divide arrives around Sep 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 Divide?

About 89 frost-free days on average, from Jun 10 to Sep 7. 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 Divide in?

USDA zone 5b 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.