Williams, AZ Frost Dates & Growing Season

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

Last spring frost
May 22
~50% chance of frost after
First fall frost
Oct 5
~50% chance of frost before
Growing season
136 days
frost-free stretch
USDA zone
≈ 6a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost May 6 May 22 Jun 10
First fall frost Oct 18 Oct 5 Sep 24
Hard freeze (28°F), median last May 9 · first Oct 15

Computed from NOAA 1991–2020 climate normals at the WILLIAMS 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 Williams

Computed from Williams'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 27 – Apr 10 May 29 – Jun 5
🫑 Peppers Mar 13 – Mar 27 Jun 5 – Jun 12
🥬 Lettuce Apr 10 – Apr 24 Apr 24 – May 8 Apr 24 – May 22
🫛 Peas Apr 10 – Apr 24
🥕 Carrots May 1 – May 22
🥦 Broccoli Apr 3 – Apr 17 May 1 – May 15
🥬 Kale Apr 10 – Apr 24 Apr 24 – May 8 Apr 24 – May 8
🥒 Cucumbers Apr 24 – May 1 May 29 – Jun 5 May 29 – Jun 5
🥒 Zucchini Apr 24 – May 1 May 29 – Jun 5 May 29 – Jun 5
🫘 Green Beans (Bush) May 29 – Jun 5
🌽 Sweet Corn May 29 – Jun 5
🌿 Basil Apr 10 – Apr 24 May 29 – Jun 5 Jun 5 – Jun 12
🧄 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 Williams's dates automatically after a lookup.

Reading the season in Williams

At about 136 frost-free days, Williams 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 Williams, AZ?

The average last spring frost in Williams is around May 22, 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 Williams, AZ?

The average first fall frost in Williams 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 Williams?

About 136 frost-free days on average, from May 22 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 Williams in?

USDA zone 6a 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.