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State guide

Planting zones in Washington

Washington spans USDA zones 6a to 9b across its 599 ZIP codes, so there is no single zone for the state and anyone who gives you one is rounding. 36% of its ZIP codes are zone 8b; the rest are not.

USDA zones 6a–9b 8 zones across the state
ZIP codes 599 599 have a NOAA station within range
Weather stations 154 In Washington, NOAA 1991–2020 normals

Your ZIP code

Get the exact answer for your address

Everything above describes Washington 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.

Works for all 40,502 US ZIP codes. Freeze dates need a NOAA station within 100 km; where there is none, the page says so rather than estimating one.

Which zone you are in depends where you are

Washington covers 8 hardiness zones. A guide that gives the state one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 36% in zone 8b and wrong for the other 64%. Here is the actual split, by ZIP code.

Zone ZIP codes Share  
8b 215 36%
7a 109 18%
9a 100 17%
6b 86 14%
8a 44 7%
7b 27 5%
6a 17 3%
9b 1 0%

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

Your freeze dates

Last spring freeze February 26 – June 6
First fall freeze September 4 – November 29

Those are the earliest and latest medians among the 154 stations in Washington with an ordinary freeze window — not an average, and not one station standing in for the rest. Half of years freeze later than a station's own median.

Your growing season

NOAA publishes a growing-season length for each station, and across the 154 stations in Washington it runs 94–276 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 65–89 °F , below the 90 °F point where cool-season crops reliably bolt.

The ends of each range, named

A range with no station behind it cannot be checked, and Washington has too many stations to table them all. So every figure above is reported here with the station standing at each end of it, by name and NOAA ID. No station on this page represents Washington — these are its edges, which is a different claim.

Measure Earliest / lowest Station Latest / highest Station
Last spring freeze February 26 Olga 2 SE, WA USC00456096 June 6 Davenport, WA USC00452007
First fall freeze September 4 Spokane 17 Ssw, WA USW00004136 November 29 Olga 2 SE, WA USC00456096
Growing season 94 days Davenport, WA USC00452007 276 days Olga 2 SE, WA USC00456096
Mean summer high 65 °F Long Beach Exp Stn, WA USC00454748 89 °F Smyrna, WA USC00457727

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

When to start seeds in Washington

Every spring job for 63 crop dates, counted from this state's own last spring freeze. Each is a range across all 154 stations — the earliest and latest that job falls anywhere in Washington — because no one station speaks for a whole state. The ranges are wide on purpose: that width is the state.

Crop Job When Offset
Green Onions Start indoors January 1 – April 11 8 weeks before
Peppers Start indoors January 1 – April 11 8 weeks before
Broccoli Start indoors January 15 – April 25 6 weeks before
Cabbage Start indoors January 15 – April 25 6 weeks before
Collards Start indoors January 15 – April 25 6 weeks before
Kale Start indoors January 15 – April 25 6 weeks before
Leaf Lettuce Start indoors January 15 – April 25 6 weeks before
Peas Direct sow January 15 – April 25 6 weeks before
Spinach Direct sow January 15 – April 25 6 weeks before
Sweet Potato Start indoors January 15 – April 25 6 weeks before
Tomatoes Start indoors January 15 – April 25 6 weeks before
Bok Choy Start indoors January 22 – May 2 5 weeks before
Kohlrabi Start indoors January 22 – May 2 5 weeks before
Swiss Chard Start indoors January 22 – May 2 5 weeks before
Arugula Direct sow January 29 – May 9 4 weeks before
Baby Salad Greens Direct sow January 29 – May 9 4 weeks before
Beets Direct sow January 29 – May 9 4 weeks before
Green Onions Direct sow January 29 – May 9 4 weeks before
Mustard Greens Direct sow January 29 – May 9 4 weeks before
Okra Start indoors January 29 – May 9 4 weeks before
Radishes Direct sow January 29 – May 9 4 weeks before
Turnips Direct sow January 29 – May 9 4 weeks before
Cabbage Set out February 5 – May 16 3 weeks before
Carrots Direct sow February 5 – May 16 3 weeks before
Collards Direct sow February 5 – May 16 3 weeks before
Collards Set out February 5 – May 16 3 weeks before
Cucumbers Start indoors February 5 – May 16 3 weeks before
Green Onions Set out February 5 – May 16 3 weeks before
Kale Direct sow February 5 – May 16 3 weeks before
Kale Set out February 5 – May 16 3 weeks before
Kohlrabi Direct sow February 5 – May 16 3 weeks before
Kohlrabi Set out February 5 – May 16 3 weeks before
Leaf Lettuce Direct sow February 5 – May 16 3 weeks before
Pumpkins Start indoors February 5 – May 16 3 weeks before
Summer Squash Start indoors February 5 – May 16 3 weeks before
Winter Squash Start indoors February 5 – May 16 3 weeks before
Zucchini Start indoors February 5 – May 16 3 weeks before
Bok Choy Direct sow February 12 – May 23 2 weeks before
Bok Choy Set out February 12 – May 23 2 weeks before
Broccoli Set out February 12 – May 23 2 weeks before
Cilantro Direct sow February 12 – May 23 2 weeks before
Leaf Lettuce Set out February 12 – May 23 2 weeks before
Swiss Chard Direct sow February 12 – May 23 2 weeks before
Swiss Chard Set out February 12 – May 23 2 weeks before
Dill Direct sow February 19 – May 30 1 week before
Bush Beans Direct sow March 5 – June 13 1 week after
Cucumbers Set out March 5 – June 13 1 week after
Pumpkins Direct sow March 5 – June 13 1 week after
Pumpkins Set out March 5 – June 13 1 week after
Summer Squash Direct sow March 5 – June 13 1 week after
Summer Squash Set out March 5 – June 13 1 week after
Sweet Corn Direct sow March 5 – June 13 1 week after
Tomatoes Set out March 5 – June 13 1 week after
Winter Squash Direct sow March 5 – June 13 1 week after
Winter Squash Set out March 5 – June 13 1 week after
Zucchini Direct sow March 5 – June 13 1 week after
Zucchini Set out March 5 – June 13 1 week after
Cucumbers Direct sow March 12 – June 20 2 weeks after
Okra Direct sow March 12 – June 20 2 weeks after
Okra Set out March 12 – June 20 2 weeks after
Peppers Set out March 12 – June 20 2 weeks after
Southern Peas Direct sow March 12 – June 20 2 weeks after
Sweet Potato Set out March 12 – June 20 2 weeks after

The week offsets are conventional extension guidance and vary by variety; the freeze dates they are counted from are measured. For a single date rather than a range, run when do I start my seeds? with your own ZIP code.

What survives the winter changes across Washington

Of 74 perennial fruits, nuts, berries, vegetables and herbs, 58 come through the winter in zone 7a and only 40 in zone 9b. Winter hardiness runs on the zone alone, so each row below is exact for the ZIP codes in it.

Zone ZIPs Survive Fail for being too warm
6a 17 51 of 74 0
6b 86 51 of 74 0
7a 109 58 of 74 1
7b 27 56 of 74 3
8a 44 57 of 74 8
8b 215 54 of 74 11
9a 100 46 of 74 25
9b 1 40 of 74 32

The best zone in Washington is 7a, which is not its mildest — 9b is. The count peaks in the middle and falls both ways, because the warm end loses plants to insufficient winter chill and summer heat rather than to cold. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the heat that comes with it. See the full list with reasons.

Your own ZIP

Work out your own dates

Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.

Metro areas in Washington

13 metro areas here have its own page, with the freeze dates from every station serving it, a spring calendar built from those stations, and every ZIP code in it listed with that ZIP code's exact zone and nearest station.

Counties in Washington

14 countys here have its own page, listing every ZIP code in it with that ZIP code's exact zone and nearest station. These are the smaller places outside the metro areas above — where most of Washington's ZIP codes actually are.

Other states to compare

All 52 states · All 388 metro areas · All county pages

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.

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

The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates, growing seasons and summer highs are NOAA's 1991–2020 Climate Normals, read from every station in Washington. Which ZIP codes are in Washington comes from the Census ZIP-to-county relation, since a county's federal code begins with its state's. Nothing here is estimated.

This page names no single station for Washington on purpose. Picking one to represent a state sounds reasonable and is not — the same reason the metro pages refuse it, only more so at this size. Instead every range names the station at each end, so you can check both without either one being made to speak for the state.

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