Is this a question on English or Geography?
US time is always behind Asian time.
HK/China is in the same time zone as Malaysia/Singapore so your time is the same as mine.
US is divided into quite a number of time zones.
Eastern USA is 12 hours behind us, i.e. it is 0800 hrs on Saturday in NY whereas the West Coast is about 16 hours behind, so the time there is 0400 hrs. The time difference is reduced by 1 hr when there is daylight saving.
Interested in Language