All time zones are measured from a starting point centered at England’s Greenwich Observatory. This point is known as the Greenwich Meridian or the Prime Meridian. Time at the Greenwich Meridian is known as Greenwich Mean Time (GMT) or Universal Time.

More Than 24 Time Zones If each time zone were 1 hour apart, there would be 24 in the world. However, the International Date Line (IDL) creates 3 more. Also, several time zones are only 30 or 45 minutes apart, increasing the total number of standard time zones even further.

As Earth rotates on its axis, it moves about 15 degrees every 60 minutes. After 24 hours, it has completed a full rotation of 360 degrees. The scientists used this information to divide the planet into 24 sections or time zones. Each time zone is 15 degrees of longitude wide.

1878

Sir Sandford Fleming

GMT-4 timing GMT-04 is a time offset that subtracts 4 hours from Greenwich Mean Time (GMT). It is observed in the AMT, AST, BOT, CLT, COST, FKT, GYT, PYT, VET during standard time, and in the CDT, EDT during the other months (Daylight saving time).

London, United Kingdom is the same time as Dublin, Ireland. Distance from Dublin to London.

There’s more daylight in the evenings and less in the mornings (sometimes called Daylight Saving Time). When the clocks go back, the UK is on Greenwich Mean Time (GMT).

London is on Greenwich Mean Time (GMT) only during winter months. The GMT time zone has the same hour offset (GMT+0) as the Western European Standard Time Zone. When Daylight Saving Time starts, London and the whole of UK are on British Summer Time (BST), which is GMT+1.

How to call London from the USA:

1. Start with 011 — the exit code for the US and Canada.
2. Next, enter 44 — the country code for the UK.
3. Then, dial 20 — the London area code (landlines only*).
4. Last, enter the local 8-digit London phone number.

Greenwich Mean Time is used as standard time all year round in the following countries and areas:

• Burkina Faso.
• The Gambia.
• Ghana.
• Guinea.
• Guinea-Bissau.
• Iceland.
• Ivory Coast.
• Liberia.

Standard Time

• Russia time zone 5 – Omsk Time (OMST)
• Kazakhstan – Almaty Time (ALMT)
• Kyrgyzstan (KGT)
• Bangladesh (BST)
• Bhutan (BTT)
• British Indian Ocean Territory.

The United States is split into six standard time zones – Hawaii, Alaska, Pacific, Mountain, Central and Eastern. The UK is five hours ahead of New York, six hours ahead of Chicago, seven hours ahead of Denver, and eight hours ahead of California.

What are the time differences between the UK and the USA?

• New York = five hours behind the UK.
• Chicago = six hours behind the UK.
• Denver = seven hours behind the UK.
• California = eight hours behind the UK.
• Alaska = nine hours behind the UK.
• Hawaii = ten hours behind the UK.

26 hours