WASHINGTON (AP) – It’ll be a sleepy Sunday morning for millions of Americans, who will lose an hour’s sleep this weekend with the return of daylight-saving time.

Officially, clocks for most of the country change at 2 a.m. Sunday. People who fail to spring forward will be an hour late for church, work or other activities.

Daylight-saving time brings an extra hour of evening sunshine until Oct. 31, when standard time returns.

Safety advocates say it’s also a good time to replace batteries in smoke detectors.

Some parts of the nation don’t observe daylight-saving time. They include Arizona, Hawaii, the part of Indiana in the Eastern time zone, Puerto Rico, the U.S. Virgin Islands and American Samoa.

Time on the Net:

National Institute of Standards and Technology: http://nist.time.gov/

U.S. Naval Observatory: http://tycho.usno.navy.mil/what.html