aikavyöhykerajoihin

Aikavyöhykerajoihin, or time zone borders, are the lines on maps that divide the Earth into different time zones. These boundaries are not always perfectly straight and often follow political or geographical features. The primary purpose of time zones is to standardize time for practical purposes, such as transportation, communication, and daily life. Without them, the sun would rise and set at different times relative to the clock in different locations, causing widespread confusion.

The concept of time zones was first widely adopted in the late 19th century, largely due to the development of railways. Before standardized time zones, each town or city often kept its own local solar time, which made coordinating train schedules incredibly difficult. The International Meridian Conference in 1884 established a global system of time zones based on the Prime Meridian (0 degrees longitude) passing through Greenwich, London.

Most time zone borders are based on lines of longitude, typically every 15 degrees, which corresponds to one hour of time difference. However, many countries and regions adjust these theoretical boundaries to align with their political borders or to keep entire countries or states within a single time zone for administrative ease. This can result in irregular or jagged time zone lines. Islands and remote regions can also have their own unique time zones. Daylight saving time, where clocks are advanced by an hour during warmer months, further complicates the practical application of time zones in some regions, creating even more frequent shifts in time zone boundaries for part of the year.