美國共有四個(gè)時(shí)區(qū)：美國西部、中西部、中部、東部。美國西部與中部相比慢兩個(gè)小時(shí)，與東部相比慢三個(gè)小時(shí)，而美國西部當(dāng)?shù)嘏c北京時(shí)間相比，夏季慢十五個(gè)小時(shí)，冬季慢十六個(gè)小時(shí)。

美國本土劃分為四個(gè)時(shí)區(qū)，再加夏威夷及阿拉斯加：

太平洋時(shí)區(qū) (pacific time): 9am (washington, oregon, neveda, california)

山地時(shí)區(qū) (montain time): 10am (montana, wyoming, idaho, utah, colorado, arizona, new mexico and parts of north dakota, south dakota and nebraska)

中部時(shí)區(qū) (central time): 11am (parts of north dakota, south dakota and nebraska, kansas, oklahoma, texas, minnesota, iowa, missouri, arkansas, louisiana wisconsin, illinois, tennessee, mississippi, alabama)

東部時(shí)區(qū)(eastern time): 12noon (michigan, indiana, ohio, kentucky, georgia, new york, pennsylvania, west virginia, virginia, north carolina, south carolina, florida, washington dc, new jersey, connecticut, ehode island, massachusetts, new hampshire, vermont, maine)

夏威夷時(shí)區(qū) (hawaii time): 7am

阿拉斯加時(shí)區(qū) (alaska time): 8am