Colors:
Color settings generally only affect Original Graphs that have been a staple of many longtime users (ex Day Detail Graph and Original 7 Day Detail, Mobile inclusive).

Different combinations of MultiColor Backgrounds, Bar Colors, Highlighing, etc. May effect MultiColor Background consistancy. An example is the Day Detail Graphs which mostly require darker backgrounds. Additional background options are available on the Original 7 Day Graph using the Background toggle link.

Color Settings Lifetime:
Selecting a Zip Code once a month normally will keep your settings, though load controls can sometimes override settings.