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A Walk Through Time - A history of timekeeping, from the days when celestial bodies acted as our clocks, through sundials, mechanical and quartz timepieces, right up to the establishment of time zones.
British Horological Institute (BHI) - The BHI was founded in the Clerkenwell district of London in 1858. A group of watchmakers joined together in an attempt to combat the large quantity of clocks and watches flooding into the country from abroad, and to raise the standards of British horology. The Institute grew rapidly and within a year it found permanent premises and started both a library and museum. it soon organised evening classes in watchmaking and clockmaking and set the first examinations in technical horology.
Calculate Time Between Two Dates - This service calculates the duration, counting the number of years, months, days, hours, minutes and seconds between two moments in time. If you only need the day count, without hours/minutes/seconds fields, please see the Date duration calculator instead.
Calendar (U.S.) - Print your own perpetual calendar for any year, month or period of months. Also includes holidays for any particular year.
ChronoZoom - An interactive timeline for all of history. Studies all 13.7 billion years from the Big Bang to the present. ChronoZoom is a step toward enabling users to browse knowledge, rather than searching, by linking relevant online resources to fixed time scales in an organized and logical manner. ChronoZoom is a tool for instructors, students and the general public to discover new knowledge through information organization. Click or scroll to navigate through events and timelines.
Compete Sun and Moon Data for One Day - Times of sunrise, sunset, moonrise, moonset, transits of the Sun and Moon, and the beginning and end of civil twilight, along with information on the Moon's phase.
Coordinated Universal Time (UTC) - Coordinated Universal Time (UTC), also referred to as Greenwich Mean Time (GMT), Universal Time (UT), or Zulu is an international time scale used in astronomical and aviation publications, weather products, and other documents. UTC uses 24-hour (military) time notation and is based on the local standard time on the 0° longitude meridian which runs through Greenwich, England. Midnight in Greenwich corresponds to 00:00 UTC, noon corresponds to 12:00 UTC, and so on.
Coordinated Universal Time (Wikipedia) - Coordinated Universal Time (UTC) is a high-precision atomic time standard. UTC has uniform seconds defined by International Atomic Time (IAT), with leap seconds announced at irregular intervals to compensate for the earth's slowing rotation, and other discrepancies. The leap seconds allow UTC to closely track Universal Time (UT), which is a time standard based on the earth's angular rotation, rather than a uniform passage of seconds. Time zones around the world are expressed as positive or negative offsets from UTC. In this role, UTC is also referred to as Zulu time (Z).
Coordinated Universal Time: Converting Between UTC and AM/PM Time - Coordinated Universal Time (UTC) can be considered equivalent to Greenwich Mean Time (GMT) (when fractions of a second are not important). UTC is the system used to indicate time in meteorology and is recommended for all general timekeeping applications. Time on most weather maps is given given in Coordinated Universal Time.
Coordinated Universal Time (UTC): Definition - Time scale, based on the second (SI), as defined and recommended by the CCIR, and maintained by the Bureau International des Poids et Mesures (BIPM). For most practical purposes associated with the Radio Regulations,UTC is equivalent to mean solar time at the prime meridian (0° longitude), formerly expressed in GMT. [NTIA] [RR] Note 1: The maintenance by BIPM includes cooperation among various national laboratories around the world. Note 2: The full definition of UTC is contained in CCIR Recommendation 460-4. (188) Note 3 : The second was formerly defined in terms of astronomical phenomena. When this practice was abandoned in order to take advantage of atomic resonance phenomena ("atomic time") to define the second more precisely, it became necessary to make occasional adjustments in the "atomic" time scale to coordinate it with the workaday mean solar time scale, UT-1, which is based on the somewhat irregular rotation of the Earth. Rotational irregularities usually result in a net decrease in the Earth's average rotational velocity, and ensuing lags of UT-1 with respect to UTC. Note 4: Adjustments to the atomic, i.e.,UTC, time scale consist of an occasional addition or deletion of one full second, which is called a leap second. Twice yearly, during the last minute of the day of June 30 and December 31, Universal Time, adjustments may be made to ensure that the accumulated difference between UTC and UT-1 will not exceed 0.9 s before the next scheduled adjustment. Historically, adjustments, when necessary, have usually consisted of adding an extra second to the UTCtime scale in order to allow the rotation of the Earth to "catch up." Therefore, the last minute of the UTC time scale, on the day when an adjustment is made, will have 59 or 61 seconds. Synonyms World Time, Z Time, Zulu Time.
Cosmic Calendar - A method to visualize the vast history of the universe in which its 13.8 billion year lifetime is condensed down into a single year. In this visualization, the Big Bang took place at the beginning of January 1 at midnight, and the current moment is mapped onto the end of December 31 at midnight. Also see The Cosmic Calendar in a Google Calendar format.
Daylight Time - Starting in 2007, daylight time begins in the United States on the second Sunday in March and ends on the first Sunday in November. On the second Sunday in March, clocks are set ahead one hour at 2:00 a.m. local standard time, which becomes 3:00 a.m. local daylight time. On the first Sunday in November, clocks are set back one hour at 2:00 a.m. local daylight time, which becomes 1:00 a.m. local standard time. These dates were established by Congress in the Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
Event Time Announcer - Converts the time of your planned event to local times all over the world for easy sharing and linking.
Local Times Around the World - This guide attempts to list all of the world's countries, and many of its islands, with a pointer to the local time in the region. Times quoted as UTC offsets do not consider Daylight Savings Time.
Military Time - Military time is an unambiguous, concise method of expressing time used by the military, emergency services (law enforcement, firefighting, paramedics), hospitals, and other entities. This site provides a detailed description of the difference between regular and military time, how military time is written, and several time conversion examples.
Naval Clock - U.S. Naval Observatory Master Clock time.
NIST: Time and Frequency Division - Maintains the standard for frequency and time interval for the United States, provides official time to the United States, and carries out a broad program of research and service activities in time and frequency metrology.
NTP Pool Project - Provides a big irtual cluster of timeservers providing reliable easy to use NTP service for millions of clients. The pool is being used by millions or tens of millions of systems around the world. It's the default "time server" for most of the major Linux distributions and many networked appliances. Also see How do I use pool.ntp.org?
Official U.S. Time - This public service is cooperatively provided by the two time agencies of U.S.: a Department of Commerce agency, the National Institute of Standards and Technology (NIST), and its military counterpart, the U. S. Naval Observatory (USNO). Readings from the clocks of these agencies contribute to world time, called Coordinated Universal Time (UTC). The time maintained by both agencies should never differ by more than 0.000 0001 seconds from UTC.
Old Style and New Style Dates - Old Style (or OS) and New Style (or NS) is used in English language historical studies either to indicate that the start of the Julian year has been adjusted to start on 1 January (NS) even though contemporary documents use a different start of year (OS); or to indicate that a date conforms to the Julian calendar (OS), formerly in use in many countries, rather than the Gregorian calendar (NS). Also see Calendar Converter.
The Time Now - A place to look for the current time of any location in the world, based on the accurate US network of cesium clocks synchronized time. Also provide other information such as daylight saving time, time zones, currencies, country calling codes, detailed weather and forecast, sunrise and sunset, moonrise & moonset, coordinates, nearby cities, nearby airports and local businesses opening times and other information when available.
Time Zone - A time zone is a region of the Earth that has adopted the same standard time, usually referred to as the local time. Most time zones are exactly one hour apart, and by convention compute their local time as an offest from Greenwich Mean Time (see also UTC). Wikipedia article.
Time.is - Check the accuracy of your clock. Find out what the exact time is right now at any of 7 million locations around the world. Compare time at different locations. Also find calendar, sunrise and sunset times, time zone locations, longitudes and latitudes, holidays and observances, and more.
TimeandDate - Local times around the world. The World Clock shows current time in all parts of the world. The Time Zone Converter calculates local time, based on a date and time in another location. Or it can be used to calculate between any other two locations. It handles past, current, and future dates and locations in 200 countries. The Sunrise and Sunset calculator shows local time, adjusted for daylight saving time for when the sun is rising or setting. The Distance Calculator calculates distance between any two cities available in the World Clock. Find lists of when DST (Daylight Saving Time) started and stopped in countries around the world in past years.
Universal Time (U.S. Naval Observatory) - The times of various events, particularly astronomical and weather phenomena, are often given in Universal Time (abbreviated UT) which is sometimes referred to, now colloquially, as Greenwich Mean Time (abbreviated GMT). The two terms are often used loosely to refer to time kept on the Greenwich meridian (longitude zero), five hours ahead of Eastern Standard Time. Times given in UT are almost always given in terms of a 24-hour clock. Thus, 14:42 (often written simply 1442) is 2:42 p.m., and 21:17 (2117) is 9:17 p.m. Sometimes a Z is appended to a time to indicate UT, as in 0935Z.
UT (Universal Time) Conversion Chart - UT is used as a basis for calculating time throughout most of the world. UT is also called Greenwich Time, Greenwich Mean Time, Zulu Time. It is the time along the prime meridian (0 longitude) that runs through the Greenwich Observatory outside of London, UK, where the current system originated. UT is tied to the rotation of the Earth in respect to the fictitious "mean Sun," which gives equal 24-hour days throughout the year. Greenwich Mean Time (GMT) was measured from Greenwich Mean at midday until 1925, when the reference point was changed from noon to midnight and the name changed to Universal Time.UT, GMT and UTC can be used interchangeably. UT conversion is fairly easy. Just add a specified number of hours to UT time to determine your time. All you need to know is your time zone and if / when your state or country enforces Daylight Saving Time. If it does, you add an additional hour to Universal Time during that time of the year.
What is UTC? - Coordinated Universal Time (UTC) is the international time standard. It is the current term for what was commonly referred to as Greenwich Meridian Time (GMT). Zero (0) hours UTC is midnight in Greenwich England, which lies on the zero longitudinal meridian. Universal time is based on a 24 hour clock, therefore, afternoon hours such as 4 pm UTC are expressed as 16:00 UTC (sixteen hours, zero minutes).
World Time Scales and Time Zones - In the latter part of the nineteenth century, a variety of meridians were used for longitudinal reference by various countries. For a number of reasons, the Greenwich meridian was the most popular of these. At least one factor in this popularity was the reputation for reliability and correctness of the Greenwich Observatory's publications of navigational data. It became clear that shipping would benefit substantially from the establishment of a single "prime" meridian, and the subject was finally resolved in 1884 at a conference held in Washington, where the meridian passing through Greenwich was adopted as the initial or prime meridian for longitude and timekeeping. Given a 24 hour day and 360 degrees of longitude around the earth, it is obvious that the world's 24 time zones have to be 15 degrees wide, on average. The individual zone boundaries are not straight, however, because they have been adjusted for the convenience and desires of local populations.
World Time Server - Correct, current, local times. Get correct world time with accurate daylight saving clock adjustments for every zone. Use converter for future events and even check current international weather conditions.
WORLDTIME - Interactive world atlas, information on local time as well as sunrise and sunset times in several hundred cities, and a database of public holidays worldwide.
Worldtimeserver - Provides correct and current time in any world time zone, country or major city. Accurate adjustments for Daylight Saving Time (or Summer Time) are made according to each location's rules and laws. Tools, clocks, time converter (UTC/GMT).
KWSnet is an Internet subject directory providing special attention to U.S. national and international news, the arts, computing, culture, environment, law, literature, media, politics, science and technology. Based in San Francisco, California, KWSnet contains over 150,000 annotated links to resources worldwide. Use Search KWSnet, located at the top of each page, to search within this site. Use Ctrl-F (Windows) or ⌘-F (Mac) to search within individual pages.