Every October, there's a week when Europe and the U.S. are out of sync with daylight saving time, potentially confusing people organizing international meetings. Most countries don't observe daylight saving time, but those that do, like Europe and North America, change clocks on different dates. In the U.K. and Europe, clocks go back on the last Sunday in October. In the U.S. and Canada, it's the first Sunday in November. This creates a temporary one-hour change in the time difference between London and New York, for example. The idea of daylight saving time dates back centuries but became law in many countries in the early 20th century.
