Time Zones and Daylight Saving: A Practical Guide for Remote Teams

Coordinated Universal Time (UTC) is the reference. Each zone is described by its offset: India is UTC+5:30, Japan UTC+9, New York UTC−5 in winter. To convert, subtract the source offset to get UTC, then add the target offset. The catch is that an offset is not fixed for a place — it depends on the date.

Many countries move clocks forward in spring to shift daylight into the evening. The United States, UK and Europe, and parts of Australia do so — but India, China, Japan, Singapore and the UAE do not. Using the IANA time-zone data, in 2026 the clocks change on these dates (in the Northern Hemisphere the first is spring forward and the second is fall back; in Australia the seasons are reversed, so the April date is the autumn change back and the October date the spring change forward):

The US and UK changes are a few weeks apart in both spring and autumn, which produces short periods when the usual New York–London gap of five hours becomes four or six.

Because India stays put, the gap to the West changes. Nine a.m. in India on 5 October 2026 is Sunday, October 4, 2026 · 23:30 in New York; on 12 January 2027 a 21:00 call in Mumbai is Tuesday, January 12, 2027 · 15:30 in London. The time zone converter reads each zone’s offset for the exact date, so conversions near a clock change stay correct.

On a 24-hour UTC axis, each team’s 9-to-5 looks like a bar. Where bars overlap, people are working at the same time:

Notice how the New York and London bars keep their relative position, but India’s overlap with both shifts by an hour, and Sydney moves the opposite way because its summer is our winter.

• Write times with zone and date: “09:00 IST, Tue 5 October”.
• Use 24-hour time to avoid am/pm confusion.
• Check meetings that fall in the weeks when the US and Europe change clocks on different dates.
• Remember a time can not exist: when clocks spring forward an hour, 2:30 a.m. never happens that day, and the converter warns you.
• Share calendar invites with the time zone attached so each person sees their local time automatically.

For related date maths see the days between dates and business days calculators.

When no time works for everyone, rotate the burden instead of always asking the same region to meet at 6 a.m. or 10 p.m. Alternate meeting times week by week, record meetings so people can watch asynchronously, and keep decisions in writing so that those who miss the call are not excluded. Agree a short list of overlap hours that are sacred for live collaboration and protect everything else for focused work. Review the schedule each time clocks change, because an arrangement that worked in winter can quietly become unfair after the shift.