Plummer 3 WSW, ID Frost Dates & Growing Season

The two dates every Plummer 3 WSW garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 11
~50% chance of frost after
First fall frost
Oct 5
~50% chance of frost before
Growing season
147 days
frost-free stretch
USDA zone
≈ 6b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 25 May 11 Jun 4
First fall frost Oct 21 Oct 5 Sep 15
Hard freeze (28°F), median last Apr 22 · first Oct 19

Computed from NOAA 1991–2020 climate normals at the PLUMMER 3 WSW 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 Plummer 3 WSW

Computed from Plummer 3 WSW's own frost dates. Click any crop for the full zone-6 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Mar 16 – Mar 30 May 18 – May 25
🫑 Peppers Mar 2 – Mar 16 May 25 – Jun 1
🥬 Lettuce Mar 30 – Apr 13 Apr 13 – Apr 27 Apr 13 – May 11
🫛 Peas Mar 30 – Apr 13
🥕 Carrots Apr 20 – May 11
🥦 Broccoli Mar 23 – Apr 6 Apr 20 – May 4
🥬 Kale Mar 30 – Apr 13 Apr 13 – Apr 27 Apr 13 – Apr 27
🥒 Cucumbers Apr 13 – Apr 20 May 18 – May 25 May 18 – May 25
🥒 Zucchini Apr 13 – Apr 20 May 18 – May 25 May 18 – May 25
🫘 Green Beans (Bush) May 18 – May 25
🌽 Sweet Corn May 18 – May 25
🌿 Basil Mar 30 – Apr 13 May 18 – May 25 May 25 – Jun 1
🧄 Garlic Fall: Aug 24 – Sep 21

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 Plummer 3 WSW's dates automatically after a lookup.

Reading the season in Plummer 3 WSW

At about 147 frost-free days, Plummer 3 WSW 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 Plummer 3 WSW, ID?

The average last spring frost in Plummer 3 WSW is around May 11, 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 Plummer 3 WSW, ID?

The average first fall frost in Plummer 3 WSW arrives around Oct 5. 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 Plummer 3 WSW?

About 147 frost-free days on average, from May 11 to Oct 5. 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 Plummer 3 WSW in?

USDA zone 6b 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.