Currently London time is 4 hours ahead of NYC time, is that always the case or does it change with daylight savings?
Okay so most of the time its 5 hours ahead, but during which period is it only 4 hours ahead? is it just for the month of march? im assuming.
No, unfortunately they make it more complicated than that, ie more work for traders for whom this matters. The US moved clocks forward on 9th March, the UK does the same on 30th March. The UK moves clocks back on 26th October this year, the US on 2nd November. Google "UK time change 2014" and "US time change 2014" and you get the dates. They are never the same and the lag is a nuisance.