The Standard Time Act established time zones and daylight saving time in 1918, but it did not last long. Daylight saving time was repealed the following year.
The Uniform Time Act of 1966 established daylight saving time throughout the United States and gave states the option to be exempt. Hawaii and most of Arizona do not follow daylight saving time. Guam, Puerto Rico, the Virgin Islands and American Samoa also have no desire to change the clock.
In 1974 and 1975, Congress expanded daytime savings to save energy during the energy crisis.
In 2007, daylight saving time reached a few more weeks, from the second Sunday in March to the first Sunday in November.
About 70 countries around the world watch the summer, but many countries near the equator do not.
But it is not universally popular. Farmers point out that their livestock do not live by clock and complain that they have to adjust their working hours to deal with animals. Plus, any parent will tell you: babies don’t get it either.