Miles City F Wiley Field, MT Frost Dates & Growing Season

The two dates every Miles City F Wiley Field garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 8
~50% chance of frost after
First fall frost
Sep 30
~50% chance of frost before
Growing season
145 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 26 May 8 May 21
First fall frost Oct 14 Sep 30 Sep 17
Hard freeze (28°F), median last Apr 29 · first Oct 8

Computed from NOAA 1991–2020 climate normals at the MILES CITY F WILEY FLD 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 Miles City F Wiley Field

Computed from Miles City F Wiley Field'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 13 – Mar 27 May 15 – May 22
🫑 Peppers Feb 27 – Mar 13 May 22 – May 29
🥬 Lettuce Mar 27 – Apr 10 Apr 10 – Apr 24 Apr 10 – May 8
🫛 Peas Mar 27 – Apr 10
🥕 Carrots Apr 17 – May 8
🥦 Broccoli Mar 20 – Apr 3 Apr 17 – May 1
🥬 Kale Mar 27 – Apr 10 Apr 10 – Apr 24 Apr 10 – Apr 24
🥒 Cucumbers Apr 10 – Apr 17 May 15 – May 22 May 15 – May 22
🥒 Zucchini Apr 10 – Apr 17 May 15 – May 22 May 15 – May 22
🫘 Green Beans (Bush) May 15 – May 22
🌽 Sweet Corn May 15 – May 22
🌿 Basil Mar 27 – Apr 10 May 15 – May 22 May 22 – May 29
🧄 Garlic Fall: Aug 19 – Sep 16

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 Miles City F Wiley Field's dates automatically after a lookup.

Reading the season in Miles City F Wiley Field

At about 145 frost-free days, Miles City F Wiley Field 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 Miles City F Wiley Field, MT?

The average last spring frost in Miles City F Wiley Field is around May 8, 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 Miles City F Wiley Field, MT?

The average first fall frost in Miles City F Wiley Field arrives around Sep 30. 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 Miles City F Wiley Field?

About 145 frost-free days on average, from May 8 to Sep 30. 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 Miles City F Wiley Field 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.