Time Zones Explained: A Complete Guide

Time zones divide the world into regions that share the same standard time. Understanding them is essential for global communication and scheduling.

How Time Zones Work

The Earth is divided into 24 major time zones, each roughly 15 degrees of longitude wide. UTC (Coordinated Universal Time) serves as the reference point. Zones east of the Prime Meridian are ahead of UTC, while zones west are behind.

History of Time Zones

Before standardized time zones, each city kept its own local time based on the sun. The expansion of railroads in the 19th century made this impractical. In 1884, the International Meridian Conference established the system we use today.

Daylight Saving Time

Many regions shift their clocks forward in spring and back in fall to maximize daylight during waking hours. Not all countries observe DST, and dates of change vary by region. This creates confusion for international scheduling.

Unusual Time Zones

Some zones use half-hour or 45-minute offsets. India uses UTC+5:30, Nepal uses UTC+5:45, and the Chatham Islands use UTC+12:45. These fractional offsets exist for geographic or political reasons.

Best Practices

Always store times in UTC in databases. Convert to local time only for display. Use our Timezone Converter and Meeting Planner to coordinate across zones effectively.