Did the brightness change?

[Schlipps]

It does not seem to be my laptop and other users expirience the same .. the colors and brightness look different. More screaming .. more bright in a negative way .. or is it me? :)

[Trigintiljon]

I don't know if we're talking about the same thing, but I've had something similar happen. Usually it has gone back to normal after I update my graphics drivers, but it could just be a coincidence. Have also had it turn back to original randomly. Haven't figured out what it is really.

[Nogbad]

Possible somebody's dropped one of those joke buffs on your island, alongside the obvious snow and greyscale ones, there's also a summer and autumn variant which change the hue/vibrancy of the colour scheme.
Check the zone wide buffs icon on the top bar to make sure you haven't got one of those running.