Black Mtn, WY Frost Dates & Growing Season

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

Last spring frost
May 14
~50% chance of frost after
First fall frost
Oct 3
~50% chance of frost before
Growing season
142 days
frost-free stretch
USDA zone
≈ 5a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 29 May 14 Jun 1
First fall frost Oct 18 Oct 3 Sep 20
Hard freeze (28°F), median last May 1 · first Oct 12

Computed from NOAA 1991–2020 climate normals at the BLACK MTN 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 Black Mtn

Computed from Black Mtn'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 Mar 19 – Apr 2 May 21 – May 28
🫑 Peppers Mar 5 – Mar 19 May 28 – Jun 4
🥬 Lettuce Apr 2 – Apr 16 Apr 16 – Apr 30 Apr 16 – May 14
🫛 Peas Apr 2 – Apr 16
🥕 Carrots Apr 23 – May 14
🥦 Broccoli Mar 26 – Apr 9 Apr 23 – May 7
🥬 Kale Apr 2 – Apr 16 Apr 16 – Apr 30 Apr 16 – Apr 30
🥒 Cucumbers Apr 16 – Apr 23 May 21 – May 28 May 21 – May 28
🥒 Zucchini Apr 16 – Apr 23 May 21 – May 28 May 21 – May 28
🫘 Green Beans (Bush) May 21 – May 28
🌽 Sweet Corn May 21 – May 28
🌿 Basil Apr 2 – Apr 16 May 21 – May 28 May 28 – Jun 4
🧄 Garlic Fall: Aug 22 – Sep 19

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 Black Mtn's dates automatically after a lookup.

Reading the season in Black Mtn

At about 142 frost-free days, Black Mtn 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 Black Mtn, WY?

The average last spring frost in Black Mtn is around May 14, 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 Black Mtn, WY?

The average first fall frost in Black Mtn arrives around Oct 3. 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 Black Mtn?

About 142 frost-free days on average, from May 14 to Oct 3. 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 Black Mtn in?

USDA zone 5a 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.