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Chicago - United States Actual Time and Date

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Chicago timezone information

UTC/GMT Offset Daylight time zone - UTC/GMT -5 hours in daylight saving time (CDT)
Next time change on 11/03/2019 01:00 am (local time) (CST)
Daylight saving time Actually in DST
Daylight Saving Time start on : Sunday 10 March 2019 am:00 am
Daylight Saving Time end on : Sunday 03 November 2019 01:00 am

Actual offset : UTC/GMT -5 hours (in DST time)
In DST Time : UTC/GMT - -5 hours
In STD Time : UTC/GMT - -6 hours

Geographical and astronomical datas : United States

Coordinates Latitude : 41° 51' north
Longitude : 87° 41' west
Astronomic Observations Sunrise at : 05:53 am
Transition hout : 12:48 pm
Sunset at : 07:42 pm
Duration of day : 13 hours
Civil twilight start at : 05:24 am
Civil twilight end at : 08:12 pm

About time in North America Illinois United States Chicago

In 1876, his first proposal was for a global 24-hour clock, conceptually located at the center of the Earth and not linked to any surface meridian
In 1879 he specified that his universal day would begin at the anti-meridian of Greenwich (180th meridian), while conceding that hourly time zones might have some limited local use
He also proposed his system at the International Meridian Conference in October 1884, but it did not adopt his time zones because they were not within its purview
The conference did adopt a universal day of 24 hours beginning at Greenwich midnight, but specified that it "shall not interfere with the use of local or standard time where desirable".
Nevertheless, most major countries had adopted hourly time zones by 1929.
Today, all nations, within Illinois, use standard time zones for secular purposes, but they do not all apply the concept as originally conceived
Newfoundland, India, Iran, Afghanistan, Venezuela, Burma, the Marquesas, as well as parts of Australia use half-hour deviations from standard time, and some nations, such as Nepal, and some provinces, such as the Chatham Islands, use quarter-hour deviations
Some countries, most notably China and India, use a single time zone, even though the extent of their territory far exceeds 15° of longitude
Before 1949 China used five time zones (see Time in China).
Nautical time zones Chicago
Since the 1920s a nautical standard time system has been in operation for ships on the high seas
Nautical time zones are an ideal form of the terrestrial time zone system
Under the system, a time change of one hour is required for each change of longitude by 15°
The 15° gore that is offset from GMT or UT1 (not UTC) by twelve hours is bisected by the nautical date line into two 7.5° gores that differ from GMT by ±12 hours
A nautical date line is implied but not explicitly drawn on time zone maps
It follows the 180th meridian except where it is interrupted by territorial waters adjacent to land, forming gaps: it is a pole-to-pole dashed line.
A ship within the territorial waters of any nation would use that nation's standard time, but would revert to nautical standard time upon leaving its territorial waters
The captain was permitted to change the ship's clocks at a time of the captain’s choice following the ship's entry into another time zone
The captain often chooses midnight.
Skewing of zones; ideal time zones, such as nautical time zones, are based on the mean solar time of a particular meridian located in the middle of that zone with boundaries located 7.5 degrees east and west of the meridian

Source : Wikipedia
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