Washington frost dates and planting season

Name: Washington
Address: District of Columbia, United States

When to plant vegetables here. Cover calendars (fleece, cold frame, unheated greenhouse) are on each plant’s when-to-plant page.

Washington has a long growing season, with roughly 255 frost-free days between the typical frost dates. Typical last spring frost: around March 8 (half of years later). Typical first fall frost: around November 19. Plant cool-season crops after about March 16; wait until about April 27 for warm-season crops.

Frost-free days255Mar 8 – Nov 19

Frost-free season in Washington. Based on average frost dates. Adjust a week or two for your conditions.

Cover calendars (fleece, cold frame, unheated greenhouse) live on each crop’s when-to-plant page.

Weekly possible temperature4 – 100 °F

Frost-free days255

Typical last spring frostMarch 8

Typical first fall frostNovember 19

Days suitable for warm-season vegetables189 (April 27 – November 1)

Days suitable for cool-season vegetables147 (March 16 – May 31; September 7 – November 15)

Calculated by Plan & Plant · Method · Data 2019–2026

Frost and suitability dates are typical figures from climate statistics. Microclimates vary; they are not a guarantee.

Frost dates calculated by Plan & Plant from Weather data by Open-Meteo.com (CC BY 4.0). Local frost pockets, valleys and coastal sites can differ by 1–3 weeks.

How we calculated this

Data: ERA5-Land via Open-Meteo, cell 38.91, -77.04, years 2019–2026 (not a 30-year climate normal yet).
Typical and safer dates: Typical last frost is the date after which half of winters in this sample had no more frost; safer is later in the sample so fewer winters still frosted.
Confidence: Provisional — short or thin sample for this place.
Full methodology (algorithm 2026-10-season-6).

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What to plant when

Cool-season vegetables

Earliest outdoor start: March 16

Suitable window: March 16 – May 31; September 7 – November 15

Cool-season crops prefer cooler weather.

Midsummer is often too hot, so suitable weeks split into more than one window.

See cool-season details

Warm-season vegetables

Earliest outdoor start: April 27

Suitable window: April 27 – November 1

Warm-season crops need mild or warm weather and cannot take frost.

Frost kills these crops, and cold snaps set them back.

See warm-season details

Green = usually good weeks to grow; blue or gray = usually too cold for that crop type.

Starter plants for Washington

Cool-season

Radish Sow: January 25 – June 7; September 4 – October 20 Planting dates
Arugula Sow: January 25 – June 7; September 4 – October 7 Planting dates
Spinach Sow: January 25 – June 7; September 4 – September 30 Planting dates
Lettuce Sow: January 25 – June 7; September 4 – September 25 Planting dates
Kale Sow: January 25 – March 21 Planting dates
Beet Sow: February 8 – August 21 Planting dates

Warm-season

Zucchini Sow: May 19 – July 13 Planting dates
Cucumber Sow: May 19 – July 13 Planting dates
Green bean Sow: May 14 – August 12 Planting dates
Tomato Transplant: May 11 – July 5 Start indoors, then transplant. Planting dates
Bell pepper Transplant: May 19 – July 9 Start indoors, then transplant. Planting dates

How these dates are judged

Last frost: The typical last spring date when frost is still expected.
First frost: The typical first fall date when frost returns.
Frost-free days: The approximate days between those two dates.
Cool-season vegetables: Crops that prefer cooler weather, such as lettuce, kale, peas, and radish.
Warm-season vegetables: Crops that need warm weather and cannot take frost, such as tomato, pepper, squash, and beans.

Cool-season planting window

Mar 16 – May 31; Sep 7 – Nov 15 (147 days)

Warm-season planting window

Apr 27 – Nov 1 (189 days)

Usually too cold

January 1 – March 15
November 16 – December 31

Weekly temperatures and planting windows

Temperatures across the year for Washington, with cool- and warm-season weeks and frost dates.

Possible min to max
Average min to max
Suitable
Tolerable
Too cold
Too hot

Selected week · tap a week or use the arrows

Week 12 · Mar 16 – Mar 22

Average 40 to 60 °F · Possible 26 to 79 °F

Cool season: tolerable

Warm season: too cold

A week is suitable for a crop type when its average low and high sit inside that type's range and its possible readings stay within the frost and heat limits (cool: 28 °F to 81 °F, warm: 32 °F to 90 °F); crossing a limit makes it tolerable, and for warm crops any chance of frost makes it too cold.

Based on average frost dates.

District of Columbia, United States · 38.91, -77.04 · 2026

Coldest weekly possible temperature4 °F

Hottest weekly possible temperature100 °F

Last expected spring frostMarch 8

First expected fall frostNovember 19

Show all 53 weeks