Alamosa 1E, CO Frost Dates & Growing Season

The two dates every Alamosa 1E garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 30
~50% chance of frost after
First fall frost
Sep 17
~50% chance of frost before
Growing season
110 days
frost-free stretch
USDA zone
≈ 5b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 17 May 30 Jun 13
First fall frost Sep 27 Sep 17 Sep 4
Hard freeze (28°F), median last May 16 · first Sep 27

Computed from NOAA 1991–2020 climate normals at the ALAMOSA 1E 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 Alamosa 1E

Computed from Alamosa 1E'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 4 – Apr 18 Jun 6 – Jun 13
🫑 Peppers Mar 21 – Apr 4 Jun 13 – Jun 20
🥬 Lettuce Apr 18 – May 2 May 2 – May 16 May 2 – May 30
🫛 Peas Apr 18 – May 2
🥕 Carrots May 9 – May 30
🥦 Broccoli Apr 11 – Apr 25 May 9 – May 23
🥬 Kale Apr 18 – May 2 May 2 – May 16 May 2 – May 16
🥒 Cucumbers May 2 – May 9 Jun 6 – Jun 13 Jun 6 – Jun 13
🥒 Zucchini May 2 – May 9 Jun 6 – Jun 13 Jun 6 – Jun 13
🫘 Green Beans (Bush) Jun 6 – Jun 13
🌽 Sweet Corn Jun 6 – Jun 13
🌿 Basil Apr 18 – May 2 Jun 6 – Jun 13 Jun 13 – Jun 20
🧄 Garlic Fall: Aug 6 – Sep 3

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 Alamosa 1E's dates automatically after a lookup.

Reading the season in Alamosa 1E

At about 110 frost-free days, Alamosa 1E 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 Alamosa 1E, CO?

The average last spring frost in Alamosa 1E is around May 30, 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 Alamosa 1E, CO?

The average first fall frost in Alamosa 1E arrives around Sep 17. 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 Alamosa 1E?

About 110 frost-free days on average, from May 30 to Sep 17. 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 Alamosa 1E 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.