Time comparisons are most reliable when they use a named regional time zone and a specific date, because UTC offsets can change.
What is a time zone?
A time zone is a set of rules used to determine local civil time in a region. Modern systems commonly identify zones with names such as Australia/Brisbane or Europe/London. The name preserves regional rules, including historical and future clock changes.
What is UTC?
Coordinated Universal Time, abbreviated UTC, is the reference used to coordinate clocks around the world. A local time is described as being ahead of or behind UTC by an offset.
Why a zone is better than an offset
An offset is only a snapshot. Two cities can share the same offset today but differ later because one observes daylight saving. A named time zone can apply the appropriate regional rule for a particular date.
WhatTimeHere formats times with your browser’s current IANA time-zone information. Device settings and software updates can affect the result, so confirm critical travel or operational times with an authoritative local source.