Frost dates for 20501Washington, DC
The average last spring frost in Washington is March 29 and the average first fall frost is November 8, giving a typical growing season of about 224 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 29
- Average first fall frost
- Nov 8
- Growing season
- 224 days
Safer after Apr 11 (1-in-10 risk)
Possible by Oct 26 (1-in-10 risk)
First frost typically in 5 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Mar 29 · Apr 10 · Apr 28 | Oct 14 · Oct 29 · Nov 10 | 200 days | 100% |
| Frost / freeze (32°F) | Mar 15 · Mar 29 · Apr 11 | Oct 26 · Nov 8 · Nov 23 | 224 days | 100% |
| Hard freeze (28°F) | Mar 2 · Mar 17 · Mar 31 | Nov 6 · Nov 20 · Dec 7 | 248 days | 100% |
Planting calendar for Washington
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Feb 26 – May 4 |
| Tomatoes | Transplant outdoors | Apr 14 – Jul 19 |
| Peppers | Start seeds indoors | Feb 26 – Mar 29 |
| Peppers | Transplant outdoors | Apr 28 – May 29 |
| Eggplant | Start seeds indoors | Mar 15 – Apr 13 |
| Eggplant | Transplant outdoors | Apr 28 – May 29 |
| Cucumbers | Sow outdoors | Apr 28 – Jul 29 |
| Summer squash | Sow outdoors | Apr 14 – May 29 |
| Winter squash & pumpkins | Sow outdoors | Apr 28 – May 29 |
| Snap beans | Sow outdoors | Apr 14 – Aug 21 |
| Sweet corn | Sow outdoors | Apr 14 – Jul 19 |
| Watermelon & cantaloupe | Sow outdoors | Apr 28 – May 29 |
| Okra | Sow outdoors | Apr 21 – May 14 |
| Peas | Sow outdoors (spring) | Feb 26 – Apr 13 |
| Potatoes | Plant outdoors (spring) | Feb 26 – Apr 28 |
| Onions | Start seeds indoors (spring) | Jan 15 – Feb 11 |
| Onions | Transplant outdoors (spring) | Mar 15 – Apr 13 |
| Broccoli | Start seeds indoors (spring) | Feb 8 – Mar 14 |
| Broccoli | Transplant outdoors (spring) | Mar 15 – Apr 13 |
| Broccoli | Start seeds indoors (fall) | Jul 9 – Jul 19 |
| Broccoli | Transplant outdoors (fall) | Aug 8 – Aug 19 |
| Cabbage | Start seeds indoors (spring) | Jan 29 – Feb 26 |
| Cabbage | Transplant outdoors (spring) | Feb 26 – Mar 29 |
| Cabbage | Start seeds indoors (fall) | Jun 29 – Jul 29 |
| Cabbage | Transplant outdoors (fall) | Jul 29 – Aug 29 |
| Leaf lettuce | Sow outdoors (spring) | Feb 26 – May 14 |
| Leaf lettuce | Sow outdoors (fall) | Jul 29 – Sep 14 |
| Spinach | Sow outdoors (spring) | Feb 19 – Apr 4 |
| Spinach | Sow outdoors (fall) | Aug 15 – Sep 19 |
| Radishes | Sow outdoors (spring) | Feb 26 – Apr 18 |
| Radishes | Sow outdoors (fall) | Jul 29 – Sep 29 |
| Kale | Sow outdoors (spring) | Mar 15 – Apr 4 |
| Kale | Sow outdoors (fall) | Jul 22 – Aug 29 |
| Carrots | Sow outdoors (spring) | Mar 29 – May 14 |
| Carrots | Sow outdoors (fall) | Jun 29 – Aug 14 |
| Garlic | Plant outdoors (fall) | Oct 29 – Nov 29 |
Where these dates come from
ZIP code 20501 is matched to the NOAA station Natl Arboretum Dc, MD, 6 km away, at 50 ft elevation (3 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Natl Arboretum Dc, MD (used) | 50 ft | Mar 29 | Nov 8 |
| Washington Reagan Ap, VA | 10 ft | Mar 24 | Nov 18 |
| Dalecarlia Rsvr, MD | 150 ft | Apr 9 | Oct 31 |
| Oxon Hill, MD | 190 ft | Apr 3 | Nov 8 |
Frost dates near Washington
- Washington, DC 20502 · last Mar 29, first Nov 8
- Naval Anacost Annex, DC 20373 · last Mar 24, first Nov 18
- Washington Navy Yard, DC 20374 · last Mar 24, first Nov 18
- Arlington, VA 22209 · last Apr 9, first Oct 31
- Fort Myer, VA 22211 · last Apr 9, first Oct 31
- Alexandria, VA 22305 · last Mar 24, first Nov 18
- Mount Rainier, MD 20712 · last Mar 29, first Nov 8
- Brentwood, MD 20722 · last Mar 29, first Nov 8
Frequently asked questions
- When is the last frost in Washington, DC?
- For ZIP code 20501, the average last spring frost (32°F) is March 29, based on NOAA 1991-2020 climate normals for the Natl Arboretum Dc, MD weather station. There is a 1-in-10 chance of a frost after April 11.
- When is the first frost in Washington, DC?
- The average first fall frost (32°F) is November 8. There is a 1-in-10 chance of frost by October 26, so tender plants are at risk from that point on.
- How long is the growing season in 20501?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 224 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.