Time & Dates

What Is Daylight Saving Time (DST)?

Daylight saving time (DST) is the practice of moving clocks forward by one hour during the warmer months so that evenings have more daylight, and back again in autumn. Not all countries use it, and those that do start and end it on different dates, which temporarily changes the time difference between regions.

How It Affects Time Zones

During DST, a region's offset from UTC changes by one hour. New York, for example, moves from UTC−5 to UTC−4.

Different Dates

The United States and European Union change clocks on different dates, so for a few weeks each year the gap between them is one hour smaller than usual.

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🔗 Related Terms

Coordinated Universal Time (UTC) 24-Hour Clock (Military Time)

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Last updated: September 27, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.