Hover your mouse over a time zone of interest.
A few notes on Universal and Local Time
Coordinated Universal Time (UTC) is a world time that is not affected by any time zone or seasonal time changes, and is defined by a network of Atomic Clocks. Historically, but incorrectly, it is often compared to Greenwich Mean Time (GMT), which is an Astronomical time (related to Earth rotation).
UTC has many applications whenever a uniform, accurate world time system is required, such as Astronomical events. UTC is also the basis for all Local (Civil) time systems in the world.
Occasionally (usually 1 January or 1 July) UTC is corrected with a leap second, to keep it within a tolerance from Astronomical time, compensating for the slowing down of Earth rotation and other natural variations.
Find more general information on UTC here.
If you want to go to the bottom of time keeping, visit the experts here.
The world is divided in time zones in which local (or civil) time is offset by a fixed amount from UTC. Most often this offset is an integer number of hours, although some countries have other offsets. However the UTC seconds are the same everywhere.
Any difference at the level of seconds in the above displays is not realistic; these services do not claim accuracy to that level.
Accurate UTC can be found on the USNO Master Clock (top right on the page)).
Daylight Saving Time
Daylight saving time (DST), (aka Summer time), is the convention of advancing clocks so that afternoons have more daylight and mornings have less.
Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn. The dates that this happens vary by location and change occasionally. In 2007 both the USA and New Zealand have changed their definition of DST.
Find more on DST here
New Zealand Standard Time (NZST) is defined as UTC + 12 hours.
During the southern summer, New Zealand has Daylight Saving Time (NZDST) which is defined as UTC + 13 hours.
NZDST starts on the last Sunday in September at 2 am when the clocks are set to 3 am.
NZDST ends on the first Sunday in April at 3 am when the clocks are set to 2 am.