By himself, Santa, his sled, and the 8 tiny reindeer can only be in one time zone at a time.

However, I don't think Santa recognizes arbitrary time zones but flies around the earth as it rotates on its axis on Christmas Eve, spending about an hour in each zone. If so, he has 24 dark earth-hours or 2440 minutes to visit all the homes that have left cookies and milk out for him.

Note: Rudolph's red-nose is only visible in the dark and Santa depends on nose-light to "guide my sleigh tonight".

It gets more complicated if you consider the length of a dark night at different latitudes. As you near the north pole, the night on December 24th lasts nearly 24 hours. Near the south pole, there are essentially no dark hours in early winter. I think if we are talking only about his route near the equator, my estimate would be close to right. Otherwise, we will need the radar sightings from TV on Christmas eve to figure out his itinerary.

Does Santa file a flight plan?