What does USDA hardiness zone 6b mean in Oregon?

Zone 6b means an average annual extreme minimum winter temperature of −5 to 0 °F — the standard USDA measure of which perennials survive winter. 27 locations in Oregon fall in this zone. It does not set planting dates; see the frost calendar below for that.

Where in Oregon's zone 6b is the growing season longest?

Brogan runs the longest season on this page at about 172 days; Jordan Valley is shortest at about 88 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.

When should I plant tomatoes in Oregon's zone 6b?

Using Bly's frost dates (this page's median-season location): start seeds indoors about Apr 5 – Apr 19, then transplant outside about Jun 7 – Jun 14. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.

Does every location in Oregon's zone 6b have the same frost dates?

No — they do not all share a weather station, so frost dates vary by a week or more across the 27 locations listed (see the table above for each location's own dates).

USDA zone 6b in Oregon

−5 to 0 °F avg. annual extreme minimum · 27 locations in this group · NOAA 1991–2020 normals

USDA plant hardiness zone 6b covers 27 locations across Oregon (average annual extreme minimum −5 to 0 °F): Baker, OR, Bend, OR, Bly, OR, Brogan, OR, Camp Sherman, OR, Crescent Lake, OR, and 21 more. Average last spring frost across this group ranges April 23 (Brogan) to June 11 (Jordan Valley), and growing seasons run 88–172 days (Jordan Valley to Brogan) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Oregon location's own frost dates; the printable planting calendar uses Bly, this group's median-season location.

USDA zone: 6b−5 to 0 °F
Last frost range: Apr 23–Jun 11avg, 32°F
First frost range: Sep 9–Oct 13avg, 32°F
Growing season range: 88–172days

Locations in this group

Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.

Own frost dates per location.
Location	Also covers	Nearest station	Last frost	First frost	Season (days)
Baker	Granite	Baker City Muni Ap	May 25	Sep 15	111
Bend	Tumalo	Bend	Jun 6	Sep 20	105
Bly *	—	Gerber Dam	May 31	Sep 21	114
Brogan	Huntington	Huntington	Apr 23	Oct 13	172
Camp Sherman	—	Marion Forks Fish Hatchery	May 15	Sep 30	134
Crescent Lake	—	Lemolo Lake 3 Nnw	Jun 1	Sep 23	115
Crooked River Ranch	Redmond, Prineville	Redmond Roberts Fld	Jun 9	Sep 14	98
Elgin	—	Elgin	May 24	Sep 18	114
Halfway	—	Halfway	May 15	Sep 24	130
John Day	Prairie, Seneca, Mount Vernon	John Day	May 28	Sep 18	113
Jordan Valley	—	Rome 2 Nw	Jun 11	Sep 10	88
Juniper Canyon	—	Barnes Stn	Jun 2	Sep 17	104
Juntura	—	Owyhee Dam	May 7	Oct 5	150
Keno	Dorris, Sprague River, Falcon Heights	Klamath Falls Intl Ap	Jun 9	Sep 18	99
La Grande	Cove, Summerville, Imbler	La Grande	May 6	Oct 1	146
Lakeview	Plush	Lakeview 2 Nnw	Jun 4	Sep 17	102
Long Creek	Greenhorn	Long Creek	Jun 5	Sep 14	99
Meacham	—	Pendleton Branch Exp Stn	May 12	Sep 27	135
Paisley	—	Paisley	Jun 6	Sep 14	98
Paisley	—	Summer Lake 1 S	Jun 8	Sep 15	96
Pilot Rock	Ukiah	Pilot Rock 1 Se	May 7	Oct 4	147
Prospect	Fort Klamath	Prospect 2 Sw	May 19	Oct 3	136
Richland	—	Richland	May 10	Oct 1	141
Shaniko	—	Antelope 6 Ssw	May 22	Oct 3	131
Three Rivers	La Pine	Wickiup Dam	Jun 7	Sep 18	100
Union	North Powder	Union	May 11	Sep 26	136
Wallowa	—	Wallowa	Jun 7	Sep 9	91

* Bly is this group's median-season location — the calendar below is computed from its data.

Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.

Planting calendar (Bly, representative)

Computed from Bly's average frost dates — the median-season location in this Oregonzone 6b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).

Crop

JanFebMarAprMayJunJulAugSepOctNovDec

Tomato

Pepper

Cucumber

Summer squash / zucchini

Start indoors
Plant out
Fall sowing
First harvest

Planting windows for Bly (Oregon, zone 6b), this group's representative location.
Crop	Frost tolerance	Start indoors	Plant out	First harvest	Fall planting	Season fit
Tomato	Tender	Apr 5 – Apr 19	Jun 7 – Jun 14	Aug 6 – Aug 26	—	matures comfortably
Pepper	Very tender	Mar 22 – Apr 5	Jun 14 – Jun 21	Aug 13 – Sep 12	—	matures, but with little margin
Cucumber	Tender	May 3 – May 10	Jun 7 – Jun 14	Jul 27 – Aug 16	—	matures comfortably
Summer squash / zucchini	Tender	—	Jun 7 – Jun 14	Jul 22 – Aug 6	—	matures comfortably
Bush bean	Tender	—	Jun 7 – Jun 14	Jul 27 – Aug 6	Jul 23 – Aug 2	matures comfortably
Sweet corn	Tender	—	May 31 – Jun 14	Jul 30 – Aug 29	—	matures comfortably
Basil	Very tender	Apr 19 – May 3	Jun 7 – Jun 14	Jul 7 – Jul 22	—	matures comfortably
Lettuce	Half-hardy	Apr 19 – May 3	May 3 – May 17	Jun 17 – Jul 2	Jul 9 – Jul 24	matures comfortably
Pea	Hardy	—	Apr 19 – May 3	Jun 13 – Jun 28	Jun 29 – Jul 14	matures comfortably
Spinach	Hardy	—	Apr 19 – May 3	May 29 – Jun 8	Jul 19 – Jul 29	matures comfortably
Carrot	Half-hardy	—	May 10 – May 17	Jul 9 – Jul 29	Jun 19 – Jul 9	matures comfortably
Broccoli	Half-hardy	Apr 5 – Apr 19	May 3 – May 17	Jun 27 – Jul 17	Jun 24 – Jul 14	matures comfortably

Which crops fit this growing season

Using Bly's own 114-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 11 of 12 crops mature here with comfortable margin, 1matures with little room to spare. The tightest fits: pepper (+9 day margin). A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.

Frost & freeze dates (Bly)

From NOAA's 1991–2020 Climate Normals at station USC00353232. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.

Freeze probabilities by temperature threshold (MM/DD, NOAA 1991–2020), Bly.
Threshold	Last spring — avg	Last spring — 90%-safe	First fall — avg	First fall — 90%-safe	Season (days)
36°F	Jun 14	Jun 30	Sep 10	Sep 21	86
32°F (freeze)	May 31	Jun 17	Sep 21	Oct 4	114
28°F	May 5	May 30	Oct 4	Oct 19	152
24°F	Apr 17	May 7	Oct 20	Nov 7	186

Growing degree days

Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 27 locations is 1,993; Bly's own reading is shown below.

Annual growing degree days for Bly (°F·days, NOAA 1991–2020).
Model	°F·days	Used for
Base 50°F (warm-season)	1,628	standard warm-season base (tomato, corn, beans)
Base 40°F (cool-season)	3,453	cool-season crops (brassicas, greens)

Hardiness zone 6b in Oregon

Zone 6b means an average annual extreme minimum winter temperature of about −5 to 0 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Oregon spans 9 hardiness zones in this dataset — see all Oregon locations for the full range, including zones5b, 6a, 7a, 7b, 8a, 8b, 9a, 9b.

Explore zone 6b in other states at zone 6b, or see all USDA hardiness zones.

Frequently asked questions

What does USDA hardiness zone 6b mean in Oregon?: Zone 6b means an average annual extreme minimum winter temperature of −5 to 0 °F — the standard USDA measure of which perennials survive winter. 27 locations in Oregon fall in this zone. It does not set planting dates; see the frost calendar below for that.
Where in Oregon's zone 6b is the growing season longest?: Brogan runs the longest season on this page at about 172 days; Jordan Valley is shortest at about 88 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
When should I plant tomatoes in Oregon's zone 6b?: Using Bly's frost dates (this page's median-season location): start seeds indoors about Apr 5 – Apr 19, then transplant outside about Jun 7 – Jun 14. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
Does every location in Oregon's zone 6b have the same frost dates?: No — they do not all share a weather station, so frost dates vary by a week or more across the 27 locations listed (see the table above for each location's own dates).

Sources & method

Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.