Saint Johns, AZ Frost Dates & Growing Season

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

Last spring frost
May 2
~50% chance of frost after
First fall frost
Oct 14
~50% chance of frost before
Growing season
165 days
frost-free stretch
USDA zone
≈ 7b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 18 May 2 May 17
First fall frost Oct 27 Oct 14 Oct 3
Hard freeze (28°F), median last Apr 19 · first Oct 23

Computed from NOAA 1991–2020 climate normals at the SAINT JOHNS 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 Saint Johns

Computed from Saint Johns's own frost dates. Click any crop for the full zone-7 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Mar 7 – Mar 21 May 9 – May 16
🫑 Peppers Feb 21 – Mar 7 May 16 – May 23
🥬 Lettuce Mar 21 – Apr 4 Apr 4 – Apr 18 Apr 4 – May 2
🫛 Peas Mar 21 – Apr 4
🥕 Carrots Apr 11 – May 2
🥦 Broccoli Mar 14 – Mar 28 Apr 11 – Apr 25
🥬 Kale Mar 21 – Apr 4 Apr 4 – Apr 18 Apr 4 – Apr 18
🥒 Cucumbers Apr 4 – Apr 11 May 9 – May 16 May 9 – May 16
🥒 Zucchini Apr 4 – Apr 11 May 9 – May 16 May 9 – May 16
🫘 Green Beans (Bush) May 9 – May 16
🌽 Sweet Corn May 9 – May 16
🌿 Basil Mar 21 – Apr 4 May 9 – May 16 May 16 – May 23
🧄 Garlic Fall: Sep 2 – Sep 30

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 Saint Johns's dates automatically after a lookup.

Reading the season in Saint Johns

Roughly 165 frost-free days gives Saint Johns gardeners room for nearly every common vegetable. Warm-season crops go out after May 2; a fall garden sown in late summer matures comfortably before the Oct 14 frost.

Frequently asked questions

When is the last frost in Saint Johns, AZ?

The average last spring frost in Saint Johns is around May 2, 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 Saint Johns, AZ?

The average first fall frost in Saint Johns arrives around Oct 14. 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 Saint Johns?

About 165 frost-free days on average, from May 2 to Oct 14. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Saint Johns in?

USDA zone 7b 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.