Well, the white blends in well in icy environments.

Well yeah but I was more talking about the standard white armor rather than the snow trooper armor; my apologies I wasn’t quite clear on that.

Well, humans have a tendency to sweat while wearing heavy body armor which leaves no skin exposed. And if humans become too overheated, they pass out from heat exhaustion. And since white materials tend to heat up less quickly than darker materials, the white coloration would make the trooper less sweaty and less likely to pass out from heat exhaustion. More specialized units like death troopers, presumably have cooling systems built into their armor.

I would also think that white armor was more of an intimidation tactic than anything else.

There are trooper variants like swamp troopers that are camouflaged.

I think white is symbolic and ideological. A sign of purity and nobility.

Clone trooper armor being white can be explained by the Kaminoans who made it. Kaminoans can see ultraviolet light. Although interiors on Kamino all seemed completely white to outside visitors, Kaminoans saw a different coloration. The same would be true for the white clone armor. We don’t have any idea what coloration clone armor appeared to the Kaminoans who created and designed it.

Not sure why the Empire continued the legacy though. Perhaps it was an attempt to show that the Empire was legitimate because it was just a continuation (or improvement) of the Republic.

Originally it was likely due to Kaminoan influence, but after the Empire phased out clones, they kept the white color scheme because it provided a notable symbol that they could use as a rallying point

One can't exactly deny the fact the stormtrooper helmet is an iconic image

It's the new line in the magazine "Galactic Fashion", duh!