[jlgreco]

Trying to use timezones to figure out what the sun is doing is already an exercise in futility: http://www.daylightmap.com/index.php

The earth's axis is tilted so in addition to needing to know the timezone and the date in a solar sense, you also need to know the latitude and need to be able to combine those three things in your head... in practice you just look it up instead.