Why are time zones sometimes different from the lines of longitude?
First off, lines of longitude are an infinite decimal system- it’s just whole numbers and the way it gets rounded that makes it appear as though there are only a few on maps. In theory time zones are every 15 degrees of longitude. In practice however, this would split up countries, cities, even neighborhoods (I’ve even heard of some places that it would split a single house into 2 time zones!), so some changes are made for administrative purposes. This is why time zone boundaries are not straight lines.