Ingomar 9 E, MT Frost Dates & Growing Season

The two dates every Ingomar 9 E garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 21
~50% chance of frost after
First fall frost
Sep 19
~50% chance of frost before
Growing season
121 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 8 May 21 Jun 4
First fall frost Oct 2 Sep 19 Sep 6
Hard freeze (28°F), median last May 10 · first Sep 28

Computed from NOAA 1991–2020 climate normals at the INGOMAR 9 E 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 Ingomar 9 E

Computed from Ingomar 9 E'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 26 – Apr 9 May 28 – Jun 4
🫑 Peppers Mar 12 – Mar 26 Jun 4 – Jun 11
🥬 Lettuce Apr 9 – Apr 23 Apr 23 – May 7 Apr 23 – May 21
🫛 Peas Apr 9 – Apr 23
🥕 Carrots Apr 30 – May 21
🥦 Broccoli Apr 2 – Apr 16 Apr 30 – May 14
🥬 Kale Apr 9 – Apr 23 Apr 23 – May 7 Apr 23 – May 7
🥒 Cucumbers Apr 23 – Apr 30 May 28 – Jun 4 May 28 – Jun 4
🥒 Zucchini Apr 23 – Apr 30 May 28 – Jun 4 May 28 – Jun 4
🫘 Green Beans (Bush) May 28 – Jun 4
🌽 Sweet Corn May 28 – Jun 4
🌿 Basil Apr 9 – Apr 23 May 28 – Jun 4 Jun 4 – Jun 11
🧄 Garlic Fall: Aug 8 – Sep 5

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 Ingomar 9 E's dates automatically after a lookup.

Reading the season in Ingomar 9 E

At about 121 frost-free days, Ingomar 9 E 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 Ingomar 9 E, MT?

The average last spring frost in Ingomar 9 E is around May 21, 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 Ingomar 9 E, MT?

The average first fall frost in Ingomar 9 E arrives around Sep 19. 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 Ingomar 9 E?

About 121 frost-free days on average, from May 21 to Sep 19. 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 Ingomar 9 E 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.