I saw the biome map and do t really have a ton of questions about it however I have some questions about the Time Zone Map.

What exactly do the colours mean? Is it offset of GMT? It doesn't say on the map. DST is optional and because Falochland is like 60°S it definitely has daylight savings. But where's the centre Time zone? Government Island?

Is 20°N also the furthest north place on the map?