美国共有四个时区：美国西部、中西部、中部、东部。美国西部与中部相比慢两个小时，与东部相比慢三个小时，而美国西部当地与北京时间相比，夏季慢十五个小时，冬季慢十六个小时。

美国本土划分为四个时区，再加夏威夷及阿拉斯加：

太平洋时区 (PACIFIC Time): 9AM (Washington, Oregon, Neveda, California)

山地时区 (Montain Time): 10AM (Montana, Wyoming, Idaho, Utah, Colorado, Arizona, New Mexico and parts of North Dakota, South Dakota and Nebraska)

中部时区 (Central Time): 11AM (Parts of North Dakota, South Dakota and Nebraska, Kansas, Oklahoma, Texas, Minnesota, Iowa, Missouri, Arkansas, Louisiana Wisconsin, Illinois, Tennessee, Mississippi, Alabama)

东部时区(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)

夏威夷时区 (Hawaii Time): 7AM

阿拉斯加时区 (Alaska Time): 8AM