If you’re asking during the summer, you’re off by an hour.Īs a side note, to make things really confusing, EST does not stand for “Eastern” – it stands for “Eastern Standard Time,” which is of course different from EDT or Eastern Daylight Time.ĭebate the merits of daylight savings time all you like, but it sure is complicated. If you’re asking them during the winter, that may be exactly what you mean. You are asking that person to meet at 4 pm EST, which is 5 pm EDT (Eastern Daylight Time), which is 2 pm MST, which is 3 pm MDT (Mountain Daylight Time). When writing an email to set up a meeting, how often do you offer times like this? Remember: When the time changes this fall, the time zone is not changing times – we are all changing time zones. It is also, currently, 9:05 AM Mountain Standard Time (MST). As I write this, it is 10:05 AM Mountain Daylight Time (MDT). Time zones do not change – ever (usually).

Which is why you might be making a typo every day…Īs mentioned above, locations that move their clocks for daylight savings time are actually changing time zones! So even though the United Kingdom is on GMT in the winter, it is on British Summer Time (plus one hour) in the summer. Some countries that follow GMT still mess with their clocks for daylight savings. Now, UTC and GMT are essentially the same thing, but you have to be very careful with that. In 1972, GMT was replaced with UTC for sciencey reasons. This was the original base time for calculating time zone offset – other time zones were plus or minus GMT so many hours. You may have heard of Greenwich Mean Time or GMT, and it is based on the sun reaching its highest point in the sky over Greenwich in the UK. One is Central Western Standard Time, an unofficial time zone in Australia that covers about 200 people, where they decided on UTC+08:45 because apparently neither Western Standard Time at +08:00 nor Central Standard Time at +09:30 were adequate. Many Americans know about the case of Arizona, which refuses to follow Daylight Savings Time (good for them), but there are even stranger instances in the world. You can make up your own time zone if you feel like it They really, really wanted to be specific with their time. However, a handful of countries use 30-minute increments, like Newfoundland Standard Time at -03:30.Īn even smaller number of time zones (three) are offset by 45 minutes, like Nepal Standard Time at +12:45. Nearly every time zone is an integer plus or minus UTC (Coordinated Universal Time), like -07:00 for Mountain Standard Time in Denver. In the course of development, I learned a lot about time zones. The list would graphically show daytime hours in each city, and how they overlapped, so you could find a good meeting time for people all over the world. It let you type in any city name (Google Maps would help you with the spelling) and add it to a list.

Years ago, I did a lot of development work on a time zone conversion tool.

Utc time plus or minus minutes