Delaware Geography & Climate

Delaware occupies the northeastern corner of the Delmarva Peninsula and is almost entirely Atlantic coastal plain — flat, low and sandy, with the highest point in the state under 450 feet.

Its northern boundary is the Twelve-Mile Circle, an arc struck twelve miles from a colonial courthouse, and the only circular state border in the country. Only the small northern tip rises into the rolling piedmont country of the Brandywine valley.

Delaware Bay forms the eastern side of the state above the coast, a broad and shallow estuary of enormous ecological importance, before the land meets the open Atlantic along its southern quarter.

Inland bays sit behind the barrier beaches in the south, and the centre of the state is farmland — maize, soya and a very large poultry industry.

Delaware is mild for its latitude because water surrounds it on three sides. Summers are warm and humid rather than extreme, and the coast runs several degrees cooler than the interior.

Winters are cool with modest snow, and coastal storms usually arrive as rain. Nor'easters are the main winter event and cause the worst coastal flooding.

Spring and autumn are long and pleasant, and autumn is the most reliable weather of the year.

Hurricanes and tropical storms are a genuine risk from August to October. The land is low and flat, so the damage is from surge and flooding rather than wind.