Everyone who works with global teams has faced the issue of how to calculate time zone offset between them and their remote team mates.
Lots of tools exist, but none that do exactly what I want. I currently use "FoxClocks" (a free plug-in for FireFox) to solve the problem of "what time is it right now in Moscow?"
(Of course, this presumes you use FireFox (or Thunderbird, or Sunbird) as your browser).
The tool throws a series of city:day:time readouts along the bottom window of the browse. You can configure the cities. It gives you a quick "at-a-glance" readout of time differences. Not as handy for figuring out what time it's going to be in Hong Kong at 09:30 on 3/1 (with this tool, you still have to do math for that), but you can at least see the differences in real time. Here's the About FoxClocks page. Some readers might find this useful.
For the "when is my meeting?" problem, I have built a little spreadsheet that I use for time offset calculation.
Here's a screen-capture of it (see above, click for a bigger version), with the offset for the summer months... I keep this on my desk, so I have a shortcut any time I'm trying to figure out when a meeting is supposed to be. Just find your city along the top row, and the city you're calling along the columns. Then, add the indicated offset to your time, and you'll have the target time (it's easier to do this in 24-hour notation).
Some useful timezone facts to remember:
- There are 40 timezones, not 24, so figuring out when your conference call is supposed to be is a big messy problem.
- Not all countries put themselves through the lunacy of "day light savings time". Here's a great info-graphic from WikiPedia about countries that do and don't use DST.
- India is all in one big time zone, called "India Standard Time" or IST. India doesn't use DST.
- China is also one big time zone at UTC +8 (CST).
- Russia has 11 time zones.
- Brazil is either 1, 2, or 3 hours ahead of the US East Coast, depending on the time of the year.