Frost dates for 56920Washington, DC
The average last spring frost in Washington is March 24 and the average first fall frost is November 18, giving a typical growing season of about 241 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 24
- Average first fall frost
- Nov 18
- Growing season
- 241 days
Safer after Apr 6 (1-in-10 risk)
Possible by Nov 5 (1-in-10 risk)
First frost typically in 32 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 20 · Apr 3 · Apr 14 | Oct 26 · Nov 6 · Nov 20 | 216 days | 100% |
| Frost / freeze (32°F) | Mar 7 · Mar 24 · Apr 6 | Nov 5 · Nov 18 · Dec 6 | 241 days | 100% |
| Hard freeze (28°F) | Feb 23 · Mar 12 · Mar 26 | Nov 14 · Dec 3 · Dec 24 | 268 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 21 – Apr 29 |
| Tomatoes | Transplant outdoors | Apr 9 – Jul 29 |
| Peppers | Start seeds indoors | Feb 21 – Mar 24 |
| Peppers | Transplant outdoors | Apr 23 – May 24 |
| Eggplant | Start seeds indoors | Mar 10 – Apr 8 |
| Eggplant | Transplant outdoors | Apr 23 – May 24 |
| Cucumbers | Sow outdoors | Apr 23 – Aug 8 |
| Summer squash | Sow outdoors | Apr 9 – May 24 |
| Winter squash & pumpkins | Sow outdoors | Apr 23 – May 24 |
| Snap beans | Sow outdoors | Apr 9 – Aug 31 |
| Sweet corn | Sow outdoors | Apr 9 – Jul 29 |
| Watermelon & cantaloupe | Sow outdoors | Apr 23 – May 24 |
| Okra | Sow outdoors | Apr 16 – May 9 |
| Peas | Sow outdoors (spring) | Feb 21 – Apr 8 |
| Potatoes | Plant outdoors (spring) | Feb 21 – Apr 23 |
| Onions | Start seeds indoors (spring) | Jan 10 – Feb 6 |
| Onions | Transplant outdoors (spring) | Mar 10 – Apr 8 |
| Broccoli | Start seeds indoors (spring) | Feb 3 – Mar 9 |
| Broccoli | Transplant outdoors (spring) | Mar 10 – Apr 8 |
| Broccoli | Start seeds indoors (fall) | Jul 19 – Jul 29 |
| Broccoli | Transplant outdoors (fall) | Aug 18 – Aug 29 |
| Cabbage | Start seeds indoors (spring) | Jan 24 – Feb 21 |
| Cabbage | Transplant outdoors (spring) | Feb 21 – Mar 24 |
| Cabbage | Start seeds indoors (fall) | Jul 9 – Aug 8 |
| Cabbage | Transplant outdoors (fall) | Aug 8 – Sep 8 |
| Leaf lettuce | Sow outdoors (spring) | Feb 21 – May 9 |
| Leaf lettuce | Sow outdoors (fall) | Aug 8 – Sep 24 |
| Spinach | Sow outdoors (spring) | Feb 14 – Mar 30 |
| Spinach | Sow outdoors (fall) | Aug 25 – Sep 29 |
| Radishes | Sow outdoors (spring) | Feb 21 – Apr 13 |
| Radishes | Sow outdoors (fall) | Aug 8 – Oct 9 |
| Kale | Sow outdoors (spring) | Mar 10 – Mar 30 |
| Kale | Sow outdoors (fall) | Aug 1 – Sep 8 |
| Carrots | Sow outdoors (spring) | Mar 24 – May 9 |
| Carrots | Sow outdoors (fall) | Jul 9 – Aug 24 |
| Garlic | Plant outdoors (fall) | Nov 8 – Dec 9 |
Where these dates come from
ZIP code 56920 is matched to the NOAA station Washington Reagan Ap, VA, 5.2 km away, at 10 ft elevation (13 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Washington Reagan Ap, VA (used) | 10 ft | Mar 24 | Nov 18 |
| Natl Arboretum Dc, MD | 50 ft | Mar 29 | Nov 8 |
| Dalecarlia Rsvr, MD | 150 ft | Apr 9 | Oct 31 |
| Oxon Hill, MD | 190 ft | Apr 3 | Nov 8 |
Frost dates near Washington
- Washington, DC 56901 · last Mar 24, first Nov 18
- 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 56920, the average last spring frost (32°F) is March 24, based on NOAA 1991-2020 climate normals for the Washington Reagan Ap, VA weather station. There is a 1-in-10 chance of a frost after April 6.
- When is the first frost in Washington, DC?
- The average first fall frost (32°F) is November 18. There is a 1-in-10 chance of frost by November 5, so tender plants are at risk from that point on.
- How long is the growing season in 56920?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 241 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.