Zonestack shows your local time big, with up to four other time zones stacked underneath: a city code, its time, the difference to your own time, a sun or moon for day or night there, and a DST tag while daylight saving time is on. Every zone is calculated from the same second as your own clock, so the minutes always change together. Times inside working hours turn green, and a +1 or -1 marks the next or previous day. Daylight saving time is calculated on the watch itself for 198 cities, so the zones stay right through every clock change without your phone. An overlap bar shows in which hours of your day everyone is inside working hours (08-20 by default), and a dot fills in when you can call right now. Prefer a dial? The 24-hour world layout puts every zone as a marker on a ring with your own day and night. WHAT IT DOES - Local time with optional seconds, plus up to 4 zones: a city, UTC/Zulu, or a fixed offset (also negative, also :30 and :45) - 198 cities in 7 regions with their own DST rules (EU, US/Canada, UK, Australia, New Zealand, Chatham, Chile, Cuba, Israel, Lebanon, Egypt) and recent changes such as British Columbia, Alberta, Manitoba, Paraguay, Mexico and Morocco without DST - Offsets like India +5:30, Nepal +5:45 and Chatham +12:45 - Amber "±1h" tag when a clock change is less than 7 days away - Day or night per city from the sun position at that city - Overlap bar with working hours you set yourself, weekend per country (Friday/Saturday where that applies), and a call-now dot - Two layouts: digital stack, or a 24-hour world ring with your day/night arc and a marker per zone - Optional date per zone instead of the time difference - Choose cities on the watch (region first, then alphabetical) or in the Connect app by name or code; your own 4-letter label if you like - 12/24 h follows the system or set it per face - Five themes, separate colors for MIP and AMOLED; always-on with dimmed zones, shifted every minute - Four optional complications (battery, steps, heart rate, notifications), empty by default; touch and hold to open the widget - Free, no key, no trial. Sister app: Meridia, a world clock app with a time converter WHAT IT NEEDS - A Garmin watch from the supported list (fēnix 6/7/8/9, epix, Forerunner 165/255/265/570/955/965/970, Venu 2/3/4/X1/Sq 2, vívoactive 4/5/6, Instinct 3 AMOLED and more) - Your own time zone comes from the watch clock (set by the phone or GPS); the other zones need nothing - DST rules follow the IANA time zone database 2026e; if a country changes its rules later, an update follows