What I do when I'm there with others, if their name shows up on the 'Members Online' list, you can click on them and it will show you where they're from. Considering the time of day or night when you're there too -- Well then you can calculate out the time zones.
It doesn't always work when peeps show up, as they just happen to stumble into the chatroom from surfing elsewhere and not necessarily signing up for anything else.
Yet as an example from our meeting up this past Thursday: Considering that I'm East Coast time; your Mountain time; Davey G is New Zealand Kiwi time, and there were plenty of others -- Shows the harpin' camaraderie we share from around the globe!
Besides, don't feel it rude or inappropriate to ask anybody where they're from or what time it is...
That's part of the fascination and fun!
See ya there!!
Keep on Harpin'!