EDT vs GMT — cities and working rhythm
US East Coast summer offset (mid-March to early November), UTC-4. The narrower gap to Europe (only 4 h during northern-hemisphere summer) means early-morning EU meetings align with reasonable East Coast times.
UK / Ireland / Iceland / Portugal / West Africa. Business hours 9 AM – 5:30 PM GMT typically. Note: London is on GMT in winter, BST (GMT+1) in summer — but "GMT" gets used loosely all year in scheduling contexts. Financial-services London anchors the European trading day.
Time gap: GMT is 4.0 hours ahead of EDT (standard-time offsets — daylight-saving flips shift this by an hour twice a year in most northern-hemisphere zones).