Redstone, MT Frost Dates & Growing Season

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

Last spring frost
May 28
~50% chance of frost after
First fall frost
Sep 7
~50% chance of frost before
Growing season
102 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 15 May 28 Jun 13
First fall frost Sep 19 Sep 7 Aug 22
Hard freeze (28°F), median last May 18 · first Sep 16

Computed from NOAA 1991–2020 climate normals at the REDSTONE 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 Redstone

Computed from Redstone'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 Apr 2 – Apr 16 Jun 4 – Jun 11
🫑 Peppers Mar 19 – Apr 2 Jun 11 – Jun 18
🥬 Lettuce Apr 16 – Apr 30 Apr 30 – May 14 Apr 30 – May 28
🫛 Peas Apr 16 – Apr 30
🥕 Carrots May 7 – May 28
🥦 Broccoli Apr 9 – Apr 23 May 7 – May 21
🥬 Kale Apr 16 – Apr 30 Apr 30 – May 14 Apr 30 – May 14
🥒 Cucumbers Apr 30 – May 7 Jun 4 – Jun 11 Jun 4 – Jun 11
🥒 Zucchini Apr 30 – May 7 Jun 4 – Jun 11 Jun 4 – Jun 11
🫘 Green Beans (Bush) Jun 4 – Jun 11
🌽 Sweet Corn Jun 4 – Jun 11
🌿 Basil Apr 16 – Apr 30 Jun 4 – Jun 11 Jun 11 – Jun 18
🧄 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 Redstone's dates automatically after a lookup.

Reading the season in Redstone

At about 102 frost-free days, Redstone 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 Redstone, MT?

The average last spring frost in Redstone is around May 28, 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 Redstone, MT?

The average first fall frost in Redstone 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 Redstone?

About 102 frost-free days on average, from May 28 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 Redstone 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.