Let's say your girlfriend sends you an angry email. It's mostly about how you behaved at the party last night and then left for a business trip without saying goodbye. You read it from the other side of the globe, jet-lagged after a 12 hour flight. You want to call and sort things out, but forget that it's now almost 3:00 am her time. After waking her up, things only get worse.

There's a new feature in Gmail Labs called Sender Time Zone that can help. Turn it on from the Labs tab under Settings, and you'll see green phone icons next to people who are probably awake and readily reachable (if it's between 9:00 am and 6:00 pm in the sender's local time zone) and red ones next to those who could be sleeping or out of the office:

Click "show details" and you can see when a message was sent in the sender's time zone as well as what time it is for them now:

Message headers always include the time sent and often include time zone info too. We use that information to show you these icons. If the time zone isn't included for a given message, this Labs feature won't display anything. Try it out and tell us what you think.