When to plant Winter squash in District of Columbia

In fall, June 20 – July 20 in Washington.

USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.

Winter squash planting dates by place in District of Columbia
PlaceSpringFall
Washington—June 20 – July 20

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for winter squash.