Buffalo Johnson Co Airport, WY Frost Dates & Growing Season

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

Last spring frost
May 13
~50% chance of frost after
First fall frost
Oct 1
~50% chance of frost before
Growing season
141 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 28 May 13 May 28
First fall frost Oct 16 Oct 1 Sep 19
Hard freeze (28°F), median last Apr 30 · first Oct 10

Computed from NOAA 1991–2020 climate normals at the BUFFALO JOHNSON CO AP 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 Buffalo Johnson Co Airport

Computed from Buffalo Johnson Co Airport'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 18 – Apr 1 May 20 – May 27
🫑 Peppers Mar 4 – Mar 18 May 27 – Jun 3
🥬 Lettuce Apr 1 – Apr 15 Apr 15 – Apr 29 Apr 15 – May 13
🫛 Peas Apr 1 – Apr 15
🥕 Carrots Apr 22 – May 13
🥦 Broccoli Mar 25 – Apr 8 Apr 22 – May 6
🥬 Kale Apr 1 – Apr 15 Apr 15 – Apr 29 Apr 15 – Apr 29
🥒 Cucumbers Apr 15 – Apr 22 May 20 – May 27 May 20 – May 27
🥒 Zucchini Apr 15 – Apr 22 May 20 – May 27 May 20 – May 27
🫘 Green Beans (Bush) May 20 – May 27
🌽 Sweet Corn May 20 – May 27
🌿 Basil Apr 1 – Apr 15 May 20 – May 27 May 27 – Jun 3
🧄 Garlic Fall: Aug 20 – Sep 17

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 Buffalo Johnson Co Airport's dates automatically after a lookup.

Reading the season in Buffalo Johnson Co Airport

At about 141 frost-free days, Buffalo Johnson Co Airport 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 Buffalo Johnson Co Airport, WY?

The average last spring frost in Buffalo Johnson Co Airport is around May 13, 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 Buffalo Johnson Co Airport, WY?

The average first fall frost in Buffalo Johnson Co Airport arrives around Oct 1. 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 Buffalo Johnson Co Airport?

About 141 frost-free days on average, from May 13 to Oct 1. 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 Buffalo Johnson Co Airport 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.