http://www.timeanddate.com/worldclock/setpersonal.html
You can add cities around the world to see what time it is in each simultaneously, then
visit this page to see the times as they are right now.
Add UTC (first in the list), and then a city that's is in your own time zone, and you'll always know.
There's also a page on that site where you can convert a future date/time in one time zone to that same time in another time zone.