How many time zones does the United States have across all 50 states?

How to get close to this number

Count the ones you can name and then add the ones you forgot. Four continental zones come to mind immediately; the states outside the contiguous landmass add two more. The question specifies all fifty states precisely because the forgotten ones are the whole point.

That omission is the classic error, and it is worth noticing as a general pattern: mental maps of a country default to its contiguous territory, so any count including outlying regions will be underestimated. The same trap appears in the France time-zone question on this site from the opposite direction.

The daylight saving detail adds a genuine complication: one state does not observe it, so the offset between it and the mainland changes twice a year. Time-zone counts describe standard offsets, and the actual difference between two places can vary seasonally depending on which observes the change — which is why scheduling across zones is harder than the count suggests.