The USA uses daylight saving time (DST). At 2am on the second Sunday in March, clocks are set one hour ahead ('spring forward'). Then on the first Sunday of November, clocks are turned back one hour ('fall back'). Just to keep you on your toes, Arizona (except the Navajo Nation) and Hawaii don't follow DST.
The US date system is written as month/day/year. Thus, 8 June 2015 becomes 6/8/15.
The continental USA has four time zones:
- EST Eastern (GMT/UTC minus five hours): NYC, Boston, Washington, DC, Atlanta
- CST Central (GMT/UTC minus six hours): Chicago, New Orleans, Houston
- MST Mountain (GMT/UTC minus seven hours): Denver, Santa Fe, Phoenix
- PST Pacific (GMT/UTC minus eight hours): Seattle, San Francisco, Las Vegas
Most of Alaska is one hour behind Pacific time (GMT/UTC minus nine hours), while Hawaii is two hours behind Pacific time (GMT/UTC minus 10 hours).
So if it’s 9pm in New York, it’s 8pm in Chicago, 7pm in Denver, 6pm in Los Angeles, 5pm in Anchorage and 4pm (November to early March) or 3pm (rest of year) in Honolulu.