UTC+13

UTC+13 is an identifier for a +13 hour time offset from UTC.
This time is used as standard time (all year round) in:

• Kiribati
  Kiribati
  Kiribati , officially the Republic of Kiribati, is an island nation located in the central tropical Pacific Ocean. The permanent population exceeds just over 100,000 , and is composed of 32 atolls and one raised coral island, dispersed over 3.5 million square kilometres, straddling the...
  
  
  • Phoenix Islands
    Phoenix Islands
    The Phoenix Islands are a group of eight atolls and two submerged coral reefs, lying in the central Pacific Ocean east of the Gilbert Islands and west of the Line Islands. They are a part of the Republic of Kiribati. During the late 1930s they became the site of the last attempted colonial...
    
     (only Kanton Island
    Kanton Island
    Kanton Island , alternatively known as "Mary Island", "Mary Balcout's Island" or "Swallow Island", is the largest, northernmost, and as of 2007, the sole inhabited island of the Phoenix Islands, in the Republic of Kiribati. It is an atoll located in the South Pacific Ocean roughly halfway between...
    
     is inhabited) (Phoenix Islands Time)
• Tonga
  Tonga
  Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
  
  

Samoa and Tokelau

At the end of 29 December 2011, Samoa

Samoa

Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...

 will advance its standard time from UTC-11

UTC-11

UTC−11 is an identifier for a time offset from UTC of −11. This time is used in:-As standard time :*American Samoa - Samoa Time Zone...

 to UTC+13 (and its daylight savings time from UTC-10 to UTC+14).

Following Samoa's decision, also Tokelau

Tokelau

Tokelau is a territory of New Zealand in the South Pacific Ocean that consists of three tropical coral atolls with a combined land area of 10 km2 and a population of approximately 1,400...

 will advance its time, in the same way of Samoa.

History

The central Pacific Republic of Kiribati introduced a change of date for its eastern half on 1 January 1995, from time zones −11 and −10 to +13 and +14, to avoid having the country divided by the date line.

Tonga has been on UTC+13 for many years. Daylight saving time was used in the southern summer seasons from 1999 to 2002.

UTC+13 was used as a daylight time (summer in Northern Hemisphere) in the parts of very eastern Russia (Chukotka and Kamchatka) that used the former Kamchatka Time

Kamchatka Time

Kamchatka Time or PETT, was a time zone in Russia, named after the Kamchatka Peninsula. It is 12 hours ahead of UTC and 9 hours ahead of Moscow Time...

. Since March 2010 these regions have switched to using Magadan Time

Magadan Time

Magadan Time or MAGT, is a time zone in Russia, named after Magadan, the administrative center of Magadan Oblast. It is twelve hours ahead of UTC and eight hours ahead of Moscow Time ....

instead.