Irkutsk Time Zone is the time zone

Time zone

A time zone is a region on Earth that has a uniform standard time for legal, commercial, and social purposes. In order for the same clock time to always correspond to the same portion of the day as the Earth rotates , different places on the Earth need to have different clock times...

 five hours ahead of Moscow Time

Moscow Time

Moscow Time is the time zone for the city of Moscow, Russia and most of western Russia, including Saint Petersburg. It is the second westernmost of the nine time zones of Russia. Moscow Time has been UTC+4 year-round since 27 March 2011....

 (MSK+5).

Before 27 March 2011, Irkutsk Time was eight hours ahead of UTC in winter (UTC+8

UTC+8

UTC+08:00 is an identifier for a time offset from UTC of +08:00. In ISO 8601 the associated time would be written as .With an estimated population of 1.53 billion living within the time zone, roughly 22.5% of the world population, it is the most populous time zone in world, as well as a possible...

) and nine hours ahead of UTC in summer (Irkutsk Summer Time (IRKST), UTC+9

UTC+9

UTC+09:00 is an identifier for a time offset from UTC of +09. This time is used in:-As standard time :*East Timor*Indonesia **Moluccas**Papua and West Papua *Japan - Japan Standard Time*North Korea...

, MSD+5).

On 27 March 2011, Russia moved to year-round daylight saving time

Daylight saving time

Daylight saving time —also summer time in several countries including in British English and European official terminology —is the practice of temporarily advancing clocks during the summertime so that afternoons have more daylight and mornings have less...

. Instead of switching between UTC+8

UTC+8

UTC+08:00 is an identifier for a time offset from UTC of +08:00. In ISO 8601 the associated time would be written as .With an estimated population of 1.53 billion living within the time zone, roughly 22.5% of the world population, it is the most populous time zone in world, as well as a possible...

 in winter and UTC+9

UTC+9

UTC+09:00 is an identifier for a time offset from UTC of +09. This time is used in:-As standard time :*East Timor*Indonesia **Moluccas**Papua and West Papua *Japan - Japan Standard Time*North Korea...

 in summer, Irkutsk Time became fixed at UTC+9

UTC+9

UTC+09:00 is an identifier for a time offset from UTC of +09. This time is used in:-As standard time :*East Timor*Indonesia **Moluccas**Papua and West Papua *Japan - Japan Standard Time*North Korea...

.

The time zone may be also referred to as Buryatia Time.