Formerly known as the GuamTime Zone, the United States Chamorro Time Zone observes a standard time by adjusting its clocks forward ten hours ahead of the Coordinated Universal Time resulting in UTC + 10:00. The clock time used within the Chamorro Time Zone is supported by the mean solar time of the 150th meridian east of the London Greenwich Observatory.
Regions which are included within the Chamorro Time Zone include the U.S territory of the Commonwealth of the Northern Mariana Islands which was first inhabited by the Chamorro people who migrated to the Islands somewhere in-between 4000 BC to 2000 BC from Southeast Asia as well as the organized unincorporated territories of the United States located in the Pacific Ocean known as Guam.
Considering the fact that none of the territories which fall under the Chamorro Time Zone recognize daylight saving time, the time used within the region is maintained as Chamorro Standard Time and is seen as fifteen hours ahead of regions which fall under the the North American and Eastern Time Zones, and two hours behind countries which are known to use the Wake Island Time Zone.
Territories which fall within the Chamorro Time Zone is recognized as almost sharing an identical time to those regions which fall within the Australian Eastern Standard Time Zone, primarily in Australia’s northeastern and second – largest populous state known as Queensland which also does not adhere to daylight saving time.
Historically, the Mariana Islands were not recognized as a part of any time zone legislated by the United States Congress Energy Policy Act of 2005 until December 23, 2000 when Public Law 106 – 564 brought about the Chamorro time zone. The standard time of Guam prior to 2000 was solely founded on the grounds of the 1959 territorial Public Law which designated the time as Guam Standard Time. This law which was constituted long before the Northern Mariana Islands became subject to United States sovereignty in 1986 remains today in the book regardless of the federal overlap.