What countries are the furthest apart time-wise. For example Japan is ahead of EST by 13 hours. Is there time zones that differ by 24 hours? And what are they? If not then what are the furthest apart?

2 answers

https://www.timeanddate.com/time/map/

For fun scoot your mouse down that jagged line in the middle of the Pacific where it is Thursday and Friday at the same moment :)
Considering major cities,
In Honolulu when the time is 1 p.m on Thursday, it's 8 a.m, Friday. The international date line lies between these two cities.