Idaho Falls 16 SE, ID Frost Dates & Growing Season

The two dates every Idaho Falls 16 SE garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Jun 9
~50% chance of frost after
First fall frost
Sep 11
~50% chance of frost before
Growing season
94 days
frost-free stretch
USDA zone
≈ 4b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 19 Jun 9 Jun 26
First fall frost Sep 27 Sep 11 Aug 27
Hard freeze (28°F), median last May 19 · first Sep 23

Computed from NOAA 1991–2020 climate normals at the IDAHO FALLS 16 SE 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 Idaho Falls 16 SE

Computed from Idaho Falls 16 SE's own frost dates. Click any crop for the full zone-4 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Apr 14 – Apr 28 Jun 16 – Jun 23
🫑 Peppers Mar 31 – Apr 14 Jun 23 – Jun 30
🥬 Lettuce Apr 28 – May 12 May 12 – May 26 May 12 – Jun 9
🫛 Peas Apr 28 – May 12
🥕 Carrots May 19 – Jun 9
🥦 Broccoli Apr 21 – May 5 May 19 – Jun 2
🥬 Kale Apr 28 – May 12 May 12 – May 26 May 12 – May 26
🥒 Cucumbers May 12 – May 19 Jun 16 – Jun 23 Jun 16 – Jun 23
🥒 Zucchini May 12 – May 19 Jun 16 – Jun 23 Jun 16 – Jun 23
🫘 Green Beans (Bush) Jun 16 – Jun 23
🌽 Sweet Corn Jun 16 – Jun 23
🌿 Basil Apr 28 – May 12 Jun 16 – Jun 23 Jun 23 – Jun 30
🧄 Garlic Fall: Jul 31 – Aug 28

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 Idaho Falls 16 SE's dates automatically after a lookup.

Reading the season in Idaho Falls 16 SE

At about 94 frost-free days, Idaho Falls 16 SE 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 Idaho Falls 16 SE, ID?

The average last spring frost in Idaho Falls 16 SE is around Jun 9, 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 Idaho Falls 16 SE, ID?

The average first fall frost in Idaho Falls 16 SE arrives around Sep 11. 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 Idaho Falls 16 SE?

About 94 frost-free days on average, from Jun 9 to Sep 11. 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 Idaho Falls 16 SE in?

USDA zone 4b 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.