Last spring frost
Mar 29
Frost Dates for Washington, DC
First fall frost
Nov 8
Growing season
224 days
Hardiness zone
7b
In an average year around Washington, DC, the last spring frost (32°F) is about Mar 29 and the first fall frost is about Nov 8, giving roughly a 224-day growing season. To be safe most years, wait until Mar 15 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Apr 28 | Apr 10 | Mar 29 |
| Freeze (32°F) | Apr 11 | Mar 29 | Mar 15 |
| Hard (28°F) | Mar 31 | Mar 17 | Mar 2 |
| Severe (24°F) | Mar 22 | Mar 7 | Feb 17 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 28 | Apr 21 | Apr 16 | Apr 13 | Apr 10 | Apr 7 | Apr 4 | Apr 1 | Mar 29 |
| 32°F | Apr 11 | Apr 6 | Apr 3 | Mar 31 | Mar 29 | Mar 27 | Mar 24 | Mar 20 | Mar 15 |
| 28°F | Mar 31 | Mar 27 | Mar 24 | Mar 20 | Mar 17 | Mar 14 | Mar 11 | Mar 7 | Mar 2 |
| 24°F | Mar 22 | Mar 17 | Mar 14 | Mar 10 | Mar 7 | Mar 3 | Feb 28 | Feb 24 | Feb 17 |
| 20°F | Mar 13 | Mar 7 | Mar 3 | Feb 28 | Feb 23 | Feb 19 | Feb 14 | Feb 7 | Jan 31 |
| 16°F | Mar 2 | Feb 25 | Feb 18 | Feb 12 | Feb 6 | Feb 2 | Jan 29 | Jan 21 | Jan 13 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 14 | Oct 29 | Nov 10 |
| Freeze (32°F) | Oct 26 | Nov 8 | Nov 23 |
| Hard (28°F) | Nov 6 | Nov 20 | Dec 7 |
| Severe (24°F) | Nov 16 | Dec 6 | Dec 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 14 | Oct 20 | Oct 24 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 10 |
| 32°F | Oct 26 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 10 | Nov 13 | Nov 17 | Nov 23 |
| 28°F | Nov 6 | Nov 11 | Nov 14 | Nov 17 | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 7 |
| 24°F | Nov 16 | Nov 23 | Nov 29 | Dec 2 | Dec 6 | Dec 10 | Dec 15 | Dec 21 | Dec 28 |
| 20°F | Dec 3 | Dec 10 | Dec 16 | Dec 22 | Dec 26 | Dec 30 | Jan 3 | Jan 9 | Jan 17 |
| 16°F | Dec 20 | Dec 27 | Jan 1 | Jan 5 | Jan 10 | Jan 14 | Jan 19 | Jan 25 | Feb 1 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Natl Arboretum Dc, Md, about 1 miles away@if(!empty($station['elevation_ft'])), at 50 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Washington, DC?
On average, the last spring frost (32°F) around Washington, DC is about Mar 29. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 15.
When is the first frost in the fall?
The first fall frost around Washington, DC typically arrives about Nov 8. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Mar 29 on average, or Mar 15 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 224 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 20018 Planting calendar → District of Columbia frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026