Frost dates for 20303Washington, 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 20303 is matched to the NOAA station Natl Arboretum Dc, MD, 4.5 km away, at 50 ft elevation (20 ft higher 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 20013 · 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 22243 · last Mar 24, first Nov 18
- Fort Myer, VA 22211 · last Apr 9, first Oct 31
- Mount Rainier, MD 20712 · last Mar 29, first Nov 8
- Brentwood, MD 20722 · last Mar 29, first Nov 8
- Alexandria, VA 22305 · last Mar 24, first Nov 18
Frequently asked questions
- When is the last frost in Washington, DC?
- For ZIP code 20303, 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 20303?
- 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.