Frost dates for Washington, District of Columbia
In Washington, half of springs have had their last frost by March 24 (and 1 spring in 10 still has one after April 6), and half of falls have had their first frost by November 18, leaving about 241 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
Washington, District of Columbia
Last spring frost
March 24
Half of springs have their last frost by this date. For a safer bet, wait until April 6: only 1 spring in 10 has a frost after that.
First fall frost
November 18
Half of falls have their first frost by this date. In 1 fall in 10 it comes by November 5.
Growing season
241 days
Frost-free days in a typical year. 9 years in 10 get at least 220.
Hardiness zone
8a
2023 USDA map: the coldest night of winter averages 10°F to 15°F. On the 2012 map it was 7a, a full zone colder. ZIP codes within about 6 miles of the city's center: 26 in 7b and 44 in 8a.
Stations near you disagree. NOAA's Washington Reagan Airport (4 miles away, at 10 feet above sea level), the one we used, gives a typical last frost of March 24 and a typical first frost of November 18. NOAA's Dalecarlia Reservoir (6 miles away, at 150 feet above sea level) gives a typical last frost of April 9 and a typical first frost of October 31. So the typical last frost could fall anywhere from March 24 to April 9 and the typical first frost from October 31 to November 18, depending on whether your garden is more like one or the other. Local terrain matters: hillsides, valley floors, water and city heat can change frost dates a lot over a few miles. Treat the dates here as a starting point, and compare with a nearby gardener or your county extension office.
Print a year planner for Washington
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | March 7 | March 24 | April 6 |
| First frost in fall | November 5 | November 18 | December 6 |
The frost-free season between them runs 241 days in a typical year. In 1 year in 10 it is 265 days or longer, and in 1 year in 10 it is 220 days or shorter.
- Hard freeze (28°F): typically last on March 12 and first on December 3. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on April 3 and first on November 6. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in Washington comes between March 7 and April 6, a window of 30 days. That is about average for NOAA's stations (the typical window is 31 days).
Planting calendar for Washington
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
We don't give a garlic date here. The rule we use, from the University of Minnesota Extension, counts from the first killing frost, and it works where a hard freeze comes every year before the ground freezes. Your county's extension office can tell you when to plant garlic in your climate.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 6 to February 3 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| January 20 to February 17 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| February | ||
| February 3 to 24 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| February 10 to 24 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| February 17 to March 3 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| February 24 to March 10 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| February 24 to March 10 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March | ||
| March 10 to 24 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| March 10 to 24 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| March 24 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| April | ||
| April 7 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| April 7 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| June | ||
| June 23 to July 7 | Cabbage for fall Start seeds | set the plants out by August 11 |
| July | ||
| July 13 to 27 | Broccoli for fall Start seeds | set the plants out by August 31 |
| August | ||
| August 22 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 26 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| August 27 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 31 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 1 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| September 5 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| September 15 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| September 25 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 5 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| November | ||
| November 5 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
Want more insurance? Shift every spring date 13 days later. That plans around April 6, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Washington Reagan Airport (station USW00013743), 4 miles from the center of Washington. It sits at about the same elevation, 10 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
Our ZIP code lookup matches these 28 ZIP codes to the same station, so they get the same dates: 20024, 20032, 20037, 20052, 20204, 20230, 20240, 20245, 20250, 20260, 20319, 20415, 20418, 20431, 20520, 20551, 20560, 20566, 20591, 22202, 22209, 22214, 22301, 22303, 22305, 22306, 22308, 22314. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- Gaithersburg, Maryland: last frost around April 1, first frost around November 6 (20 miles away)
- Baltimore, Maryland: last frost around March 24, first frost around November 21 (35 miles away)
- Frederick, Maryland: last frost around April 2, first frost around November 6 (45 miles away)
See frost dates across the District of Columbia, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.