Daylight-saving time gives way to standard time at 2 a.m. Sunday.
Except for anyone in eastern Indiana, Albania, Argentina, Australia, Israel, Iran, Iraq, Ireland, or any of dozens of countries where they made the switch weeks ago, or where they will be switching from standard to daylight time, or where they do not observe daylight time and will not be making any changes.
In these days of international travel, one would think the whole world would switch time on the same day. But no.
Most citizens of Greenland, for example, reset their watches to standard time on Sept. 26, but residents of Scoresbysund do it the next day.
And folks in Baja California will change to daylight time Sunday morning, unless they live south of the 28th parallel, in which case they will ignore the whole thing because southern Baja, like the rest of Mexico, did not adopt daylight-saving time.
Not to the airlines that fly international routes, nor to the travelers who occasionally wander into some exotic corner of the globe and tumble into a time warp.
"It's a very difficult situation, especially in Latin American countries," says Mel Olsen, who, as American Airlines' vice president of capacity planning, schedules that airline's flights. "They all want to change on different dates.
"Just within the last few weeks, Brazil told us they weren't going to change [from standard to daylight time] Oct. 17, but Oct. 24, because Argentina changes Oct. 17, and for some reason they (( don't want to do it together."
Latin America is a crazy quilt of time changes.
The Official Airline Guide includes an international time chart that takes up three pages of small type plus a map in each issue. According to the chart, the Falkland Islands changed to daylight time Sept. 13; Paraguay on Oct. 5; Chile, Oct. 11; and Uruguay, Oct. 18. Argentina will switch Nov. 1. Peru, for some reason or another, observes daylight time only from Jan. 1 to March 31.
Other Latin American countries, and some states within Brazil, do not observe daylight time at all.
Chronologically as well as geo-politically, the Mideast remains a region of chaos.
Iran, for example, changed to standard time on Sept. 23. Turkey followed Sept. 26, but Turks could get back on standard time by crossing the border to Iraq, which didn't change until Oct. 1 (along with Syria, Jordan and Egypt).
Israel accommodates Orthodox Jews, who arise to pray at dawn in the days preceding the Jewish New Year, by changing from daylight to standard time on Sept. 5, the earliest date of any country in the Northern Hemisphere.
Time-wise, even Europe, which is integrating tariffs, monetary systems and even railroad networks, cannot get its act together. Most countries switched to standard time Sept. 26, but England, Ireland, Scotland and Wales waited until Oct. 24.