Sydney is UTC+10 (GMT+10) / UTC+11 (GMT+11). New York is UTC−4 (EDT) / UTC−5 (EST). New York is currently 14 hours behind Sydney.
There is no overlap of standard business hours (09:00–17:00) between these two cities. Consider early morning or late afternoon calls where one side works slightly outside core hours.
Times shown in Sydney local time → New York local time. Based on business hours 09:00–17:00.
Sydney observes Australian Eastern Standard Time (AEST, UTC+10) in winter and Australian Eastern Daylight Time (AEDT, UTC+11) in summer. Because Sydney is in the Southern Hemisphere, its summer runs from October to April — the opposite of the Northern Hemisphere. Clocks go forward on the first Sunday in October and back on the first Sunday in April. This means that when London is entering summer (April), Sydney is leaving it; the two cities are briefly 10 hours apart instead of the usual 11 in Sydney's summer or 10 in Sydney's winter.
Sydney is Australia's largest city and its financial capital — the Australian Securities Exchange (ASX) opens at 10:00 AEST/AEDT. The city's UTC+10/+11 position means it is one of the first major financial centres to open each trading day, typically before Tokyo. Sydney is 10–11 hours ahead of London, making same-day business calls extremely difficult — an 09:00 call in Sydney is 23:00 the previous night in London. The best overlap window for Sydney–London is early Sydney morning (08:00–10:00 AEST), which corresponds to London's late evening (22:00–00:00).
Australia has a complex DST situation: New South Wales, Victoria, South Australia, and Tasmania observe DST, while Queensland, Western Australia, and the Northern Territory do not. This creates internal Australian timezone fragmentation during summer, with Sydney (AEDT, UTC+11) being 2 hours ahead of Perth (AWST, UTC+8) instead of the usual 2-hour difference in winter. International schedulers must check whether their Australian contact is in a DST-observing state before assuming "Australian Eastern Time."
New York City observes Eastern Time: UTC−5 (EST, Eastern Standard Time) from the first Sunday in November to the second Sunday in March, and UTC−4 (EDT, Eastern Daylight Time) during the remainder of the year. The Eastern Time Zone covers roughly a third of the US population and all of Canada's most populous provinces, making EST/EDT the de-facto "American" timezone in global business. The US adopted standard time nationally after the Standard Time Act of 1918, and year-round Daylight Saving Time rules were made permanent by the Energy Policy Act of 2005.
New York's financial markets — the New York Stock Exchange and NASDAQ — open at 09:30 and close at 16:00 EST/EDT, setting the rhythm for global equity trading. The city is 5 hours behind London (in winter), 14 hours behind Tokyo, and 9.5 hours behind Mumbai, which means scheduling live meetings between New York and Asia almost always requires someone to work outside normal hours. New York is 3 hours ahead of Los Angeles, so the US business day effectively runs from 06:00 Pacific to 17:00 Eastern — an 11-hour window.
The Uniform Time Act of 1966 standardised DST observance across US states, though states can opt out (Arizona does not observe DST, and Hawaii has never observed it). There are periodic debates in the US Congress about eliminating the clock change entirely, similar to EU proposals. Until such a change occurs, New York switches twice per year, occasionally causing brief periods where the offset to London or other regions differs from the norm by one hour during the transition weeks when the two regions change on different dates.
New York is currently 14 hours behind Sydney.
When it is 12:00 noon in Sydney, it is 22:00 in New York (based on current offsets — verify during DST transitions).
Sydney observes DST, changing from GMT+10 to GMT+11. New York observes DST, changing from EDT to EST.