Gresham, OR planting zone & frost dates

Gresham is in USDA hardiness zone 9a. The last spring frost usually comes around March 16 and the first fall frost around November 20, for a growing season of about 250 days.

USDA hardiness zone9aavg. extreme winter low 20°F to 25°F

Average last spring frostMarch 1690% chance of no frost after April 12

Average first fall frostNovember 2010% chance of frost by October 30

Growing season250 daysfrost-free days in an average year

Planting calendar for Gresham

Dates are counted from the average last spring frost (March 16) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.

Crop	When
Tomatoes	Start seeds indoors: Jan 19 – Feb 2 Transplant outdoors: Mar 23 – Mar 30
Peppers	Start seeds indoors: Jan 5 – Jan 19 Transplant outdoors: Mar 30 – Apr 6
Eggplant	Start seeds indoors: Jan 5 – Jan 19 Transplant outdoors: Mar 30 – Apr 6
Broccoli	Start seeds indoors: Jan 5 – Jan 19 Transplant outdoors: Feb 16 – Mar 2
Cabbage	Start seeds indoors: Jan 5 – Jan 19 Transplant outdoors: Feb 16 – Mar 2
Onions (sets)	Plant outdoors: Feb 16 – Mar 2
Peas	Sow outdoors: Feb 2 – Feb 16
Spinach	Sow outdoors: Feb 2 – Feb 16
Lettuce	Sow outdoors: Feb 16 – Mar 2
Carrots	Sow outdoors: Feb 16 – Mar 2
Potatoes	Plant outdoors: Feb 16 – Mar 2
Beans	Sow outdoors: Mar 23 – Mar 30
Sweet corn	Sow outdoors: Mar 23 – Mar 30
Cucumbers	Sow outdoors: Mar 23 – Mar 30
Squash & zucchini	Sow outdoors: Mar 23 – Mar 30
Basil	Start seeds indoors: Feb 2 – Feb 16 Transplant outdoors: Mar 23 – Mar 30

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 25 (8 weeks before the average first fall frost on Nov 20).

Frost risk in detail

	90% chance	50% chance	10% chance
Last 32°F frost in spring is after	Feb 18	Mar 16	Apr 12
First 32°F frost in fall is before	Dec 17	Nov 20	Oct 30

How to read it: in spring there is a 10% chance of a frost after April 12, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 30. A hard freeze (28°F) usually ends around February 14.

Hardiness zone by ZIP code in Gresham

97030 zone 9a
97080 zone 8b

Nearby cities

Troutdale zone 9a, last frost Mar 26
Damascus zone 8b, last frost Mar 18
Happy Valley zone 8b, last frost Mar 18
Oatfield zone 9a, last frost Mar 18
Sandy zone 8b, last frost Mar 27
Gladstone zone 9a, last frost Mar 18
Milwaukie zone 9a, last frost Feb 25
Oak Grove zone 9a, last frost Mar 18

All cities in Oregon → · Other zone 9a cities →

Questions

What growing zone is Gresham, OR?

Gresham is in USDA Plant Hardiness Zone 9a (average extreme winter low 20°F to 25°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 8b.

When is the last frost in Gresham?

The average last spring frost (32°F) in Gresham is March 16. There is still a 10% chance of frost until April 12.

When can I plant tomatoes in Gresham?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Mar 23 – Mar 30. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Portland Troutdale Ap, OR (USW00024242), 6.1 km (3.8 mi) from the city center, elevation 9 m, based on 20 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.