Leo 6 SW, WY Frost Dates & Growing Season

The two dates every Leo 6 SW 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 28
~50% chance of frost before
Growing season
131 days
frost-free stretch
USDA zone
≈ 5a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 3 May 20 Jun 13
First fall frost Oct 13 Sep 28 Sep 9
Hard freeze (28°F), median last May 6 · first Oct 8

Computed from NOAA 1991–2020 climate normals at the LEO 6 SW 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 Leo 6 SW

Computed from Leo 6 SW'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 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 17 – Sep 14

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 Leo 6 SW's dates automatically after a lookup.

Reading the season in Leo 6 SW

At about 131 frost-free days, Leo 6 SW 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 Leo 6 SW, WY?

The average last spring frost in Leo 6 SW 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 Leo 6 SW, WY?

The average first fall frost in Leo 6 SW arrives around Sep 28. 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 Leo 6 SW?

About 131 frost-free days on average, from May 20 to Sep 28. 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 Leo 6 SW 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.