The annual seasonal change from Daylight Saving Time to Standard Time becomes official at 2 a.m. this Sunday. In addition to turning clocks back one hour, local fire departments and the Red Cross are urging people to help ensure fire safety by checking their smoke alarms as part of the time switch.

It’s wise to “change the batteries in each smoke alarm at least two times per year,” said Carol Dunn, a community disaster educator for the King County chapter of Red Cross. “To make it easier to remember, make the change when you change your clocks.”

More than 90 percent of homes have smoke alarms, but one-third are estimated to have worn-out batteries or none at all and thus not working, officials said. They advised testing alarms once a month.

Oh, and if you’re wondering when Daylight Saving Time will return, mark your calendar: 2 a.m. on the second Sunday of March 2009.