Notes from Kloss, William, et al. Art in the White House: A Nation's Pride. Washington, D.C.: The White House Historical Association, 2008
"The Avenue in the Rain . . . is one of some 30 related paintings of flag-decorated streets that the artist [Childe Hassam] produced between 1916 and 1919, during and immediately after the First World War. . . . [T]hey are intensely patriotic works . . . .

". . . The avenue is Fifth Avenue, frequently decorated with American flags as American sentiment moved . . . from isolationism toward intervention. The artist's most striking device here is the projection of flags into the picture from points of unseen anchor beyond the frame . . . . In one sense the flags become the surface of the painting . . . .

"Observing shadows to be bluish rather than black, the Impressionists often became mannered in their use of blue, making it a dominant hue in many of their paintings. . . .

[H]ere the rain and the rain-slicked streets give [Hassam] an excuse for a literal wash of blue and blue-gray, enhanced by a profusion of reflections."