This is only applicable when you are on really long rides, either East to West or vice versa. A ride that takes you through different timezones. It is important to keep in mind the TZ you are currently in and the TZ you will end up at by evening. Couple of things that might get affected due to TZ are :

01. Arrival time planned might get late such that you miss your planned dinner

02. Ending up too early at your destination thinking you could have easily rode two more hours