Why does the time difference between two cities change during the year?

Because many countries switch to and from daylight saving time on different dates. In the weeks between those switches the difference is one hour smaller or larger than usual — the converter always shows the difference that applies right now.

Yes. The clocks and the difference are computed in your browser from the official IANA time zone rules for the current moment, so they are never stale.

Can I compare two cities outside my own country?

Yes — pick any two of the 50 cities, for example London and Tokyo, and you get the difference between exactly those two, with daylight saving time handled correctly on both sides.

Time zone converter – compare any two cities

How the converter works

The converter uses your browser's built-in IANA time zone data, so the numbers are always correct — including in the weeks when one of the two places has just switched to or from daylight saving time. Pick two cities, for example New York City and London, and you get each city's current local time and the difference between them at this exact moment.

A note on daylight saving time

A time difference is not a fixed number. When only one of the two cities observes daylight saving time, or the two switch on different dates, the difference shifts by an hour part of the year. The converter never uses a stored table — it evaluates the official rules for the current instant.

Frequently asked questions

Why does the time difference between two cities change during the year?: Because many countries switch to and from daylight saving time on different dates. In the weeks between those switches the difference is one hour smaller or larger than usual — the converter always shows the difference that applies right now.
Are the times live?: Yes. The clocks and the difference are computed in your browser from the official IANA time zone rules for the current moment, so they are never stale.
Can I compare two cities outside my own country?: Yes — pick any two of the 50 cities, for example London and Tokyo, and you get the difference between exactly those two, with daylight saving time handled correctly on both sides.