Did you set your clock forward for daylight savings time ?   What ? Why do we have to do that ?   Well , at the start of the spring we usually have more daylight in the mornings and less in the afternoon . This is basically due to our position on the planet and the rotation of the earth . In any case , to take better advantage of the daylight available , we compensate by moving our clocks forward one hour .   I see . That ’ s convenient ! I never understood things like this , such as GMT . I never know what time zone we are in or when to change my clock !   That just stands for Greenwich Mean Time . Here in California , we are in Pacific Standard Time , that is eight time zones west of Greenwich . Remember when we were in Beijing ? Well , then we were in China Standard Time , and that ’ s eight time zones east of Greenwich !   That ’ s why it was so weird traveling from Beijing to LA ! Because of the huge time difference , even though we left Beijing at noon and flew for more than eight hours , we still arrived in LA the same day at noon ! It ’ s like we went back in time ! 