Gmail Labs continues to make an awesome product even better. Tonight the site has introduced ‘Sender time zone’, a feature that allows users to quickly tell if their contact is likely awake or sound asleep, based on the time zone their Emails are being sent from. The feature takes advantage of the time zone data often included in Email headers, showing a green light for contacts that are probably awake and a red one for those that are asleep. For those of us who live and die by our inboxes, it can be tough to keep track of the contacts that are abroad, which can lead to some awkward phone calls (I’ve accidentally called CEOs of startups located in the UK at around 4 in the morning, their time). The feature is also helpful for determining how quickly you can expect an Emailed response from your contact (again, I’ve sent urgent messages to PR representatives who were based abroad). As with all Google Labs features (other notables include a Panic Button and Multi-Pane Viewing) users can access the feature by enabling Google Labs through their Gmail settings, then selecting ‘Sender Time Zone’.