F.lux: adjusts display color temp by time of day
justgetflux.com
justgetflux.com
Android folks should check out Twilight https://play.google.com/store/apps/details?id=com.urbandroid... - note that it works by putting a colour filtered overlay on top of the existing display content. Google does block some actions while this happens - eg accepting terms/permissions for installation of an app. Consequently you have to disable twilight when doing things like app installation/updates. (flux and redshift tweak the gamma tables directly - something that isn't available on Android.)
The transition points at sunrise and sunset are very disruptive, however. Even knowing it is coming, it will break your thought process.
(OS X, might be different on other platforms?)