When is the last frost in Washington, DC?

The average last spring frost (50% probability of 32°F) in Washington is around March 29, based on NOAA/NCEI 1991–2020 normals at the Natl Arboretum Dc, MD station (2.6 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Washington?

The average first fall frost in Washington, DC is around November 8, giving roughly a 224-day frost-free growing season.

What planting zone is Washington, DC?

Washington is in USDA plant hardiness zone 8a (average annual extreme minimum temperature 10 to 15°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Washington?

In Washington, DC the warmest month is July (avg high 89.8°F) and the coldest is January (avg low 27.8°F). It averages about 45.6″ of precipitation a year and 9.7″ of snow.

Home › District of Columbia › Washington

Washington, DC Planting Calendar & Frost Dates

USDA hardiness zone 8a · ZIP 20001 · elevation 15′ · NOAA & USDA data

Washington is in USDA hardiness zone 8a (winters can dip to 10 to 15°F), with a growing season of about 224 days between the average last spring frost (March 29) and first fall frost (November 8). The warmest month is July (avg high 89.8°F); the coldest is January (avg low 27.8°F). It averages 45.6″ of precipitation a year and 9.7″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 10 to 15°F

Last spring frost

March 29

avg (50% prob, 32°F)

First fall frost

November 8

avg (50% prob, 32°F)

Growing season

224 days

frost-free window

Warmest month

July

avg high 89.8°F

Month-by-month typical weather in Washington

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Natl Arboretum Dc, MD (2.6 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	44.7	27.8	36.2	3	4.7
February	47.8	29.5	38.6	2.8	2.3
March	55.9	36.5	46.2	4	1.4
April	67.6	46.4	57	3.4	0
May	76.9	56.6	66.7	4.3	0
June	85.4	66.1	75.7	4.6	0
July	89.8	70.9	80.3	4.6	0
August	88.4	68.8	78.6	3.7	0
September	81.7	61.5	71.6	4.1	0
October	69.9	49	59.4	4.2	0
November	58.4	38.9	48.6	3.2	0
December	49.2	31.9	40.6	3.7	1.3

What to plant when in Washington

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: February 15 · Transplant out: April 5
Peppers	warm	Start seeds indoors: February 1 · Transplant out: April 12
Cucumbers	warm	Direct sow: April 5
Zucchini / squash	warm	Direct sow: April 5
Bush beans	warm	Direct sow: April 5
Sweet corn	warm	Direct sow: April 5
Basil	warm	Transplant out: April 5
Peas	cool	Sow (spring): February 22 · Sow (fall): September 13
Spinach	cool	Sow (spring): February 15 · Sow (fall): September 13
Lettuce	cool	Sow (spring): March 1 · Sow (fall): September 13
Kale	cool	Transplant (spring): March 8 · Sow (fall): August 30
Broccoli	cool	Transplant (spring): March 15
Carrots	cool	Sow (spring): March 8 · Sow (fall): August 30
Onions	cool	Transplant (spring): March 1
Potatoes	cool	Plant seed potatoes: March 15
Radishes	cool	Sow (spring): March 1 · Sow (fall): September 27

Dates are computed from Washington's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Natl Arboretum Dc, MD, 2.6 mi (confidence: high). Monthly weather normals: Natl Arboretum Dc, MD, 2.6 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.