In the East, Purple Finches stage winter irruptions biennially, probably in response to cyclical variations in food supply. Western populations exhibit an altitudinal migration, moving to lower elevations in winter. The raspberry color is deepest on the head, nape, face, throat, breast, flanks, and rump. The hindneck, back, and scapular feathers are deep red streaked with brown. Wings and tail are brown and the belly and undertail coverts are white.
Females are quite different, lacking any red color.
The head is pale brown, with fine dark streaks, and a dark ear patch separating a broad white suprecilium and a white moustache stripe. The white moustache stripe is separated from the white of the throat by a brown malar stripe. Throat, breast, and flanks are white with heavy brown streaks. The belly and undertail coverts are unstreaked white. Males in this plumage may sing and hold territory before molting into adult plumage in their second fall.