Yukon Time Zone clocks ahead yet another hour on October 30, 1983 to adopt Alaska Standard Time (the former Yukon Standard Time), effectively changing their standard time zone by two hours. Most of the Aleutian Islands moved from the Bering Time Zone (UTC-11) to the Hawaii-Aleutian Standard Time Zone (UTC-10) (until 1983 known as the Alaska-Hawaii Standard Time Zone). Yukon Time Zone The Yukon Time Zone was a time zone that kept standard time; Yukon Standard Time (YST) was obtained by subtracting nine hours from Coordinated Universal Time (UTC) resulting in UTC−9. Yukon Daylight Time (YDT) when observed was eight hours behind UTC.
Prime Time Access Rule hour of prime time (7:00–8:00 p.m. Eastern Time and Pacific Time, 6:00–7:00 p.m. Central, Mountain, Alaska and Hawaii–Aleutian Time) as the "prime access hour". By the early 1980s, the PTAR had introduced a policy amendment prohibiting stations in the 50 television markets with the highest prime time viewership from broadcasting more than three hours of network programming during the four-hour "prime time" block. Stations had to find original programming to fill during the "prime time" fraction. However, the rule exempted certain types of programming, such as overruns of live sports events, special news, documentary and children's programming, and certain sports