The Lansdowne Portrait & Copies

In the fall of 1775 Congress chose brown as the original color for the national uniform. In October 1778, however, France sent uniforms with a predominance of blue coats (although there were also brown), and so on 2 October 1779 Congress switched to blue as the official color.

Michael Stephenson
Patriot Battles: How the War of Independence Was Fought (2007)