Time And Weather Observations
UTC - The Official Time Of Weather Measurement

Throughout the world, time weather observations are always referenced to Coordinated Universal Time or Universal Time Coordinated, also known as Universal Time or UTC. The military generally refers to it as Zulu Time or "Z Time." This international time standard was known as Greenwich Mean Time (GMT) prior to 1972, and UTC is still based on the 0° longitude (Greenwich) meridian that passes through England's Greenwich Observatory.

Maintained by the Bureau International des Poids et Mesures (BIPM) in Paris, Coordinated Universal Time is the basis for legal time worldwide, including weather observations. By the authority of the Convention of the Metre, a diplomatic treaty between fifty-one nations, the BIPM ensures world-wide uniformity of measurements and their traceability to the International System of Units (SI). The Convention mandates that time weather observations taken by Member States be recorded using UTC in 24-hour format, i.e. 0000 for midnight, 1300 for 1:00 PM, 1800 for 6:00 PM, etc.

Worldwide, official local standard time is referenced as the number of hours from UTC, depending on the number of time zones a particular locality is distant from the 0° meridian. For example, in North America the Eastern Time Zone is five time zones away from the Greenwich meridian (UTC -05:00) and consequently five hours later than UTC. Midnight (0000) Eastern Standard Time is 0500 hours UTC, five hours later than EST. Even with home weather stations, personal time and weather is not an acceptable official time and weather reference. Coordinated Universal Time is never adjusted to Daylight Savings Time, so with the advance of one hour when DST goes into effect the Eastern Time Zone is only four hours later than UTC.

The international weather and time standard of Coordinated Universal Time is used by many interests outside of the meteorological community: astronomers, radio operators, international airlines and shipping companies to name a few. And the radio controlled clock you may have in your home is updated daily using UTC.

All content on the WeatherShack Education Center is Copyright © 2007 WeatherShack.com. This material may not be reproduced, displayed, modified or distributed without the express prior written permission of WeatherShack.com. For permission, please contact support@weathershack.com

Product Search:

Customer Comments
	"Thanks so much for your diligence in helping me get this replacement part for my weather station... It's good to see that outstanding service is alive and well at Weather Shack, and I really appreciate your help." — Ed B. Albemarle, NC "This has been such a joy compared to many other places we've ordered from, I'm sure you will hear from us again." — Ted M. Perkins, OK "Thank you so much for your prompt delivery of the weather station! I was so pleased by how quickly it arrived. My husband loves it. Thanks again for the great service!" — Angie H. Troutville, VA "Thanks. I just placed my weather station order. I am ordering through you because of your timely response to my inquiry. I had emailed the same question to three other companies and you were the only person to answer. Thank you for your help and very quick service. On the net, as in real life, service is everything!!!" — Steve L. Orinda, CA "...the wireless thermometer arrived and as predicted my father was thrilled. Thank you very much for your prompt attention to this order and I will be certain to share my WeatherShack experience with others." — Ian B. West Newton, MA View More Testimonials