🇬🇧 Summary of Greenwich Mean Time

Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London. It was historically used as the international time standard before UTC was adopted.

Key Points

• Historical Standard: GMT served as the world's time reference until 1972, when UTC officially replaced it as the civil time standard.
• Usage: GMT remains the legal time in the United Kingdom during winter months and is still commonly used in Africa and Western Europe.
• Difference from UTC: GMT is based on Earth's rotation, while UTC is based on atomic time. The two are effectively the same for most practical purposes but differ slightly due to leap seconds.
• Daylight Saving: Countries that use GMT in winter (like the UK and Ireland) advance to UTC+1 during summer (British Summer Time, BST).

Source: Wikipedia