From World Afropedia
UTC−10:30 is an identifier for a time offset from UTC of −10:30.
Hawaii used a standard time of GMT−10:30 from 1900 until 1947, when clocks were changed to GMT−10:00 zone, which later was changed to UTC−10.
The air portion of the attack on Pearl Harbor in 1941 began at December 7, 7:48 a.m. Hawaiian Time and December 8, 3:18 a.m. Japanese Standard Time (UTC+09), as kept by ships of the Kido Butai. UTC time in ISO 8601 notation was 1941-12-07T18:18+00:00.
af:UTC-10:30 az:UTC−10:30 be:UTC-10:30 be-x-old:UTC-10:30 fa:یوتیسی ۱۰:۳۰- ja:UTC-10:30 ro:UTC−10:30 zh:UTC-10:30