Portland, OR Frost Dates & Growing Season

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

Last spring frost
Feb 25
~50% chance of frost after
First fall frost
Dec 1
~50% chance of frost before
Growing season
279 days
frost-free stretch
USDA zone
9a
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Jan 24 Feb 25 Mar 21
First fall frost Dec 27 Dec 1 Nov 10
Hard freeze (28°F), median last Jan 31 · first Dec 20

Computed from NOAA 1991–2020 climate normals at the Portland Kgw-Tv station (1 km from central Portland). "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 Portland

Computed from Portland's own frost dates. Click any crop for the full zone-9 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Dec 31 – Jan 14 Mar 4 – Mar 11
🫑 Peppers Dec 17 – Dec 31 Mar 11 – Mar 18
🥬 Lettuce Jan 14 – Jan 28 Jan 28 – Feb 11 Jan 28 – Feb 25
🫛 Peas Jan 14 – Jan 28
🥕 Carrots Feb 4 – Feb 25
🥦 Broccoli Jan 7 – Jan 21 Feb 4 – Feb 18
🥬 Kale Jan 14 – Jan 28 Jan 28 – Feb 11 Jan 28 – Feb 11
🥒 Cucumbers Jan 28 – Feb 4 Mar 4 – Mar 11 Mar 4 – Mar 11
🥒 Zucchini Jan 28 – Feb 4 Mar 4 – Mar 11 Mar 4 – Mar 11
🫘 Green Beans (Bush) Mar 4 – Mar 11
🌽 Sweet Corn Mar 4 – Mar 11
🌿 Basil Jan 14 – Jan 28 Mar 4 – Mar 11 Mar 11 – Mar 18
🧄 Garlic Fall: Oct 20 – Nov 17

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 Portland's dates automatically after a lookup.

Reading the season in Portland

With roughly 279 frost-free days, Portland gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Dec 1 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Portland, OR?

The average last spring frost in Portland is around Feb 25, 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 Portland, OR?

The average first fall frost in Portland arrives around Dec 1. 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 Portland?

About 279 frost-free days on average, from Feb 25 to Dec 1. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Portland in?

USDA zone 9a 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.