Time difference between Dublin and Chicago

The gap is not the same all year

Every converter gives one number for this pair. That number is right for most of the year and wrong for part of it, because Dublin goes forward on the last Sunday in March and back on the last Sunday in October and Chicago goes forward on the second Sunday in March and back on the first Sunday in November.

Both change their clocks and both are in the northern hemisphere, but not on the same weekend — Dublin goes forward on the last Sunday in March and Chicago on the second Sunday in March. For the days in between, the gap is neither party's expected figure, and a standing meeting silently moves by an hour. That mismatch is a common cause of a missed international call.

About Dublin and Chicago

Ireland is the only country whose summer time is legally the standard and whose winter time is the deviation — Irish Standard Time is UTC+1 and the clocks go *back* to UTC in October. The result is identical to Britain's and the legal description is inverted, which occasionally matters in contracts.

Chicago is UTC−6 in winter, the US Central zone, and the one people most often mean by an unqualified "CST" — a reading that collides with China Standard Time fourteen hours the other way.

What 6 hours actually costs you

The window is 2 hours wide and that is all there is. 3:00 PM–5:00 PM in Dublin is 9:00 AM–11:00 AM in Chicago, and anything outside it puts somebody at their desk when they are not meant to be. A pair this tight is worth putting in a calendar rather than agreeing each time.

When they can both be at their desks

Nine-to-five in both cities overlaps for 2 hours — 3:00 PM to 5:00 PM in Dublin, the same moment as 9:00 AM to 11:00 AM in Chicago.

Dublin

Chicago

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How far apart Dublin and Chicago are

The shortest path over the Earth's surface between the two is 5,890 km (3,660 miles). Flown along that line, an airliner at cruising speed takes roughly 7 hours 35 minutes in the air — actual routings add to it, and whether a nonstop service exists depends on the airlines rather than the distance.

Over that distance you cross 6 hours of clock, which is where jet lag comes from: the body shifts by about an hour a day, so 6 hours takes most people 6 days or so to absorb. Flying west to Chicago is the easier direction — you gain the hours, and staying up later comes more naturally than going to bed early.

Dublin to Chicago, hour by hour

On the usual gap of 6 hours.

Frequently asked questions