Zones shows one moment in time across the cities you care about — pick a time and base city, and see it everywhere at once, with the day offset flagged so you never book a call at 3 a.m. by mistake. Add or remove cities freely. Everything runs on your device.

Time

Base city

Add a city

Times are computed with your browser's own timezone database (Intl), so daylight-saving shifts are handled automatically for the date you pick. A red badge marks a different calendar day (+1 / −1). Everything runs on your device.