Time in Mongolia
From Wikipedia, the free encyclopedia
Time in Mongolia is officially represented by the Mongolian Standard Time (UTC+08:00). However, the far western provinces of Khovd, Uvs and Bayan-Ölgii use UTC+07:00.

Daylight saving time
Mongolia used daylight saving time in 1983–1998, 2001–2006[1] and 2015–2016.[2] However, Mongolia observes time almost exactly an hour ahead of its geographical time zone, with its border between UTC+7 and UTC+8 being almost exactly the longitudinal line of 97.5° E(which is really the designated border for between UTC+7 and UTC+6), so all of Mongolia could be said to be on permanent daylight/summer time.
IANA time zone database
The IANA time zone database contains two zones for Mongolia in the file zone.tab.