What causes different time zones?

Great question! Different time zones exist because the Earth rotates once every 24 hours, causing different parts of the planet to experience daylight and darkness at different times. To keep local time aligned with the position of the sun in the sky—essentially, to have “noon” occur when the sun is highest overhead—time zones were created. Here’s how it works: The Earth is divided into 360 degrees of longitude. Since it rotates 360 degrees in 24 hours, it turns about 15 degrees every hour (360° ÷ 24 hours = 15° per hour). To standardize time, the world is divided into roughly 24 time zones, each spanning about 15 degrees of longitude. Within each zone, the clocks are set to the same standard time, usually differing by one hour from the neighboring zones. This system means that as you travel east, local time generally moves forward by one hour for each time zone, and as you travel west, it moves back by one hour. The International Date Line, roughly along the 180° longitude, serves as the “reset” point where the date changes. In practice, political and geographic factors also influence the exact boundaries of time zones, so they often don’t follow perfect 15-degree segments. Countries may adjust their time zones for convenience, economic ties, or daylight saving time. In summary, time zones are a practical way to coordinate local time with the Earth’s rotation and the position of the sun, ensuring that our clocks reflect the natural cycle of day and night wherever we are.