There are 4 standard time zones for the continental United States:
- Eastern time zone
- Central time zone (+1 hour)
- Mountain time zone (+1 hour)
- Pacific time zone (+1 hour)
The time difference between New York on east coast and Los Angeles on west coast is 3 hours
But in total there 9 standard time zones in the US: Atlantic, Eastern, Central, Mountain, Pacific, Alaska, Hawaii, Samoa and Chamorro.