What USDA hardiness zone is Klamath County, Oregon?

Klamath County, Oregon spans USDA hardiness zones 6a to 7a. 65% of its ZIP codes are zone 6b, so there is no single zone for the county.

When is the last spring frost in Klamath County, Oregon?

The median last spring freeze runs May 19 – June 9 across the 8 NOAA weather stations serving Klamath County, Oregon, from NOAA 1991-2020 Climate Normals. Half of years freeze later than the median.

Oregon

Planting zones in Klamath County, Oregon

This county spans USDA zones 6a to 7a, so there is no single zone for Klamath County and anyone who gives you one is rounding. 65% of its ZIP codes are zone 6b; the rest are not.

USDA zones 6a–7a 3 zones across 17 ZIP codes

ZIP codes 17 17 have a NOAA station within range

Weather stations 8 NOAA 1991–2020 normals, across 5,950 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Klamath County, Oregon as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.

The growing season in Klamath County is closing

Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives September 14 – October 3 across the 8 NOAA stations serving this county .

Your next season already has a date

The first job of it is 🧅 Green Onions, start indoors, around March 24 – April 14 — counted back from a last spring freeze of May 19 – June 9 here.

Every spring date for your ZIP →

These are ranges across the whole county. The ZIP lookup above gives the dates from your own nearest station instead.

All 8 stations agreeAt least one station

Every one of the 8 NOAA stations serving this county counts June 9 – September 14 as growing season (97 days). Widening to any single station gives May 19 – October 3 (137 days).

That is a 40-day difference inside one county — which is why this page gives ranges rather than a single planting date. The ZIP lookup above resolves it to one station.

Which zone you are in depends where you are

Klamath County covers 3 hardiness zones. A guide that gives the county one zone has picked whichever is largest and rounded everyone else into it — fine for the 65% in zone 6b and wrong for the other 35%. Here is the actual split.

Zone	ZIP codes	Share
6b	11	65%
6a	5	29%
7a	1	6%

Zones are published per ZIP code, so yours is exact even though the county's is not. The hardiness tool will tell you which one you are in.

Your freeze dates

Last spring freeze May 19 – June 9

First fall freeze September 14 – October 3

Across the 8 NOAA stations serving this county. These are medians — half of years freeze later than the date shown — so treat the later end of each range as the cautious one.

The growing season runs 97–136 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 75.4–85.3 °F in June–August. Summer rain over the same months runs 1.2–4.0" across those 7 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. The middle station covers about 15% of it, so a summer garden here is watered rather than rained on. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 82 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Klamath County

Zones are published per ZIP code, not per county, so this is the exact answer rather than the county's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.

ZIP code	USDA zone	Nearest NOAA station	Distance
97601	7a	Howard Prairie Dam, OR	34.7 km
97603	6b	Klamath Falls INTL AP, OR	5.2 km
97604	6b	Prospect 2 SW, OR	37.0 km
97621	6a	Gerber Dam, OR	35.9 km
97622	6b	Gerber Dam, OR	23.1 km
97623	6b	Gerber Dam, OR	14.9 km
97624	6a	Klamath Falls INTL AP, OR	45.8 km
97625	6b	Klamath Falls INTL AP, OR	22.0 km
97626	6b	Prospect 2 SW, OR	41.1 km
97627	6b	Keno, OR	14.3 km
97632	6b	Tulelake, CA	10.2 km
97633	6b	Tulelake, CA	11.0 km
97634	6b	Klamath Falls INTL AP, OR	6.6 km
97639	6a	Klamath Falls INTL AP, OR	36.7 km
97731	6a	Lemolo Lake 3 Nnw, OR	42.2 km
97733	6b	Lemolo Lake 3 Nnw, OR	24.7 km
97737	6a	Wickiup Dam, OR	21.2 km

ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.

When to start seeds in Klamath County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 8 of them, because no one station speaks for the county.

Crop	Job	When	Offset
🧅 Green Onions	Start indoors	March 24 – April 14	8 wk before
🌶️ Peppers	Start indoors	March 24 – April 14	8 wk before
🥦 Broccoli	Start indoors	April 7 – April 28	6 wk before
🥬 Cabbage	Start indoors	April 7 – April 28	6 wk before
🥬 Collards	Start indoors	April 7 – April 28	6 wk before
🥬 Kale	Start indoors	April 7 – April 28	6 wk before
🥬 Leaf Lettuce	Start indoors	April 7 – April 28	6 wk before
🫛 Peas	Direct sow	April 7 – April 28	6 wk before
🥬 Spinach	Direct sow	April 7 – April 28	6 wk before
🍠 Sweet Potato	Start indoors	April 7 – April 28	6 wk before
🍅 Tomatoes	Start indoors	April 7 – April 28	6 wk before
🥬 Bok Choy	Start indoors	April 14 – May 5	5 wk before
🥬 Kohlrabi	Start indoors	April 14 – May 5	5 wk before
🥬 Swiss Chard	Start indoors	April 14 – May 5	5 wk before
🥬 Arugula	Direct sow	April 21 – May 12	4 wk before
🥬 Baby Salad Greens	Direct sow	April 21 – May 12	4 wk before
🥕 Beets	Direct sow	April 21 – May 12	4 wk before
🧅 Green Onions	Direct sow	April 21 – May 12	4 wk before
🥬 Mustard Greens	Direct sow	April 21 – May 12	4 wk before
🌶️ Okra	Start indoors	April 21 – May 12	4 wk before
🌱 Radishes	Direct sow	April 21 – May 12	4 wk before
🥔 Turnips	Direct sow	April 21 – May 12	4 wk before
🥬 Cabbage	Set out	April 28 – May 19	3 wk before
🥕 Carrots	Direct sow	April 28 – May 19	3 wk before
🥬 Collards	Direct sow	April 28 – May 19	3 wk before
🥬 Collards	Set out	April 28 – May 19	3 wk before
🥒 Cucumbers	Start indoors	April 28 – May 19	3 wk before
🧅 Green Onions	Set out	April 28 – May 19	3 wk before
🥬 Kale	Direct sow	April 28 – May 19	3 wk before
🥬 Kale	Set out	April 28 – May 19	3 wk before
🥬 Kohlrabi	Direct sow	April 28 – May 19	3 wk before
🥬 Kohlrabi	Set out	April 28 – May 19	3 wk before
🥬 Leaf Lettuce	Direct sow	April 28 – May 19	3 wk before
🎃 Pumpkins	Start indoors	April 28 – May 19	3 wk before
🎃 Summer Squash	Start indoors	April 28 – May 19	3 wk before
🎃 Winter Squash	Start indoors	April 28 – May 19	3 wk before
🥒 Zucchini	Start indoors	April 28 – May 19	3 wk before
🥬 Bok Choy	Direct sow	May 5 – May 26	2 wk before
🥬 Bok Choy	Set out	May 5 – May 26	2 wk before
🥦 Broccoli	Set out	May 5 – May 26	2 wk before
🌿 Cilantro	Direct sow	May 5 – May 26	2 wk before
🥬 Leaf Lettuce	Set out	May 5 – May 26	2 wk before
🥬 Swiss Chard	Direct sow	May 5 – May 26	2 wk before
🥬 Swiss Chard	Set out	May 5 – May 26	2 wk before
🌿 Dill	Direct sow	May 12 – June 2	1 wk before
🫘 Bush Beans	Direct sow	May 26 – June 16	1 wk after
🥒 Cucumbers	Set out	May 26 – June 16	1 wk after
🎃 Pumpkins	Direct sow	May 26 – June 16	1 wk after
🎃 Pumpkins	Set out	May 26 – June 16	1 wk after
🎃 Summer Squash	Direct sow	May 26 – June 16	1 wk after
🎃 Summer Squash	Set out	May 26 – June 16	1 wk after
🌽 Sweet Corn	Direct sow	May 26 – June 16	1 wk after
🍅 Tomatoes	Set out	May 26 – June 16	1 wk after
🎃 Winter Squash	Direct sow	May 26 – June 16	1 wk after
🎃 Winter Squash	Set out	May 26 – June 16	1 wk after
🥒 Zucchini	Direct sow	May 26 – June 16	1 wk after
🥒 Zucchini	Set out	May 26 – June 16	1 wk after
🥒 Cucumbers	Direct sow	June 2 – June 23	2 wk after
🌶️ Okra	Direct sow	June 2 – June 23	2 wk after
🌶️ Okra	Set out	June 2 – June 23	2 wk after
🌶️ Peppers	Set out	June 2 – June 23	2 wk after
🫘 Southern Peas	Direct sow	June 2 – June 23	2 wk after
🍠 Sweet Potato	Set out	June 2 – June 23	2 wk after

Offsets are published guidance; the dates they land on are computed from measured NOAA normals. The seed-starting tool does this for your own ZIP code and counts the days.

What survives the winter changes across Klamath County

Zone 7a carries 58 of 74 perennial edibles; zone 6a carries 51. The best number is not always the warmest zone — the count peaks in the middle and falls both ways, because the warm end loses plants to insufficient winter chill and summer heat, not to cold.

Hardiness ranges are a judgement, published by growers rather than measured; the zone they are compared against is measured. On a warm-end verdict, check with your local extension service — a coastal zone 8 and an inland zone 8 are not the same summer.

Cautious — shortens the seasonMedian across stationsOptimistic

Last spring freeze: Plan to July 2 to be careful. Median May 19 – June 9 across 8 stations; April 29 is the optimistic end.
First fall freeze: Plan to August 30 to be careful. Median September 14 – October 3 across 8 stations; October 20 is the optimistic end.

NOAA publishes these as probabilities, not averages — the middle figure is a median, so half of years fall either side of it. The cautious end is the 10% tail: in roughly nine years in ten the freeze falls on the safe side of it.

The 8 stations behind these numbers

All 8 NOAA stations whose normals this page quotes, spanning about 191 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole county.

A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.

These are the stations this county's ZIP codes actually cite as nearest — not a claim that each one sits inside its boundary, since a rural ZIP legitimately reaches over it. Every figure above comes from them, and each is named so you can check it.

Station	NOAA ID	Last spring freeze	First fall freeze	Season
Gerber Dam, OR	USC00353232	May 31	September 21	114 days
Howard Prairie Dam, OR	USC00354060	June 8	September 24	108 days
Keno, OR	USC00354403	June 5	September 20	107 days
Klamath Falls INTL AP, OR	USW00094236	June 9	September 18	99 days
Lemolo Lake 3 Nnw, OR	USC00354835	June 1	September 23	115 days
Prospect 2 SW, OR	USC00356907	May 19	October 3	136 days
Tulelake, CA	USC00049053	June 6	September 14	97 days
Wickiup Dam, OR	USC00359316	June 7	September 18	100 days

These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.

Your own ZIP

Work out your own dates

This page describes a whole county. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.

Other places to compare

Klamath County sits in Oregon. That page carries the whole state's zone spread, its metro areas, and every other county in it with a page here.

More of Oregon

Counties with the same zones — 6a–7a

Matched on the exact zone set, not a dominant zone, so the winter answer on these pages really is the same one as here.

Gear

If you want to act on this

Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.

Trunk wrapZone 6a is cold enough that winter sun on a young trunk does more damage than the cold does.
Row cover and frost clothThe season here closes at the first fall freeze dated above — a cover buys back some of those days at the end.
MulchFor the perennials nearest their cold limit in zone 6a, where an insulated crown is what decides whether they come back.

As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.

Sources

Where these numbers come from

Hardiness zones are the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. Freeze dates and growing-season lengths are NOAA 1991–2020 Climate Normals, taken per station and cited above by name and NOAA ID.

County boundaries come from the Census ZCTA-to-county relation, which is what places each ZIP code — and which treats parishes, boroughs and census areas as county equivalents. No station is chosen to represent this county: every range above is taken across all of them and the count is stated, because picking one would be a judgement dressed as a measurement.