Grand Lake 6 SSW, CO Frost Dates & Growing Season

The two dates every Grand Lake 6 SSW garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Jun 13
~50% chance of frost after
First fall frost
Sep 7
~50% chance of frost before
Growing season
86 days
frost-free stretch
USDA zone
≈ 5b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Jun 1 Jun 13 Jun 28
First fall frost Sep 21 Sep 7 Aug 21
Hard freeze (28°F), median last May 26 · first Sep 22

Computed from NOAA 1991–2020 climate normals at the GRAND LAKE 6 SSW 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 Grand Lake 6 SSW

Computed from Grand Lake 6 SSW'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 Apr 18 – May 2 Jun 20 – Jun 27
🫑 Peppers Apr 4 – Apr 18 Jun 27 – Jul 4
🥬 Lettuce May 2 – May 16 May 16 – May 30 May 16 – Jun 13
🫛 Peas May 2 – May 16
🥕 Carrots May 23 – Jun 13
🥦 Broccoli Apr 25 – May 9 May 23 – Jun 6
🥬 Kale May 2 – May 16 May 16 – May 30 May 16 – May 30
🥒 Cucumbers May 16 – May 23 Jun 20 – Jun 27 Jun 20 – Jun 27
🥒 Zucchini May 16 – May 23 Jun 20 – Jun 27 Jun 20 – Jun 27
🫘 Green Beans (Bush) Jun 20 – Jun 27
🌽 Sweet Corn Jun 20 – Jun 27
🌿 Basil May 2 – May 16 Jun 20 – Jun 27 Jun 27 – Jul 4
🧄 Garlic Fall: Jul 27 – Aug 24

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 Grand Lake 6 SSW's dates automatically after a lookup.

Reading the season in Grand Lake 6 SSW

At about 86 frost-free days, Grand Lake 6 SSW 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 Grand Lake 6 SSW, CO?

The average last spring frost in Grand Lake 6 SSW is around Jun 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 Grand Lake 6 SSW, CO?

The average first fall frost in Grand Lake 6 SSW arrives around Sep 7. 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 Grand Lake 6 SSW?

About 86 frost-free days on average, from Jun 13 to Sep 7. 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 Grand Lake 6 SSW in?

USDA zone 5b 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.