It's that time again. The UK, continental Europe, and various other places have moved out of Daylight Saving Time while most of North America waits another week for its time shift.
NEVER, NEVER, NEVER depend on your expectation of time offsets to help you coordinate meetings between different geographies.
"New York is 5 hours behind London."
Not this week!
If you schedule meetings or promote live webinars, look up the starting times in different cities and provide a time conversion link for interested participants. I use www.timeanddate.com, which is very good about staying current with changes to time zones and local times around the world. Local time definitions are completely arbitrary and change more frequently than you might imagine.
https://www.timeanddate.com/worldclock/meeting.html lets you quickly scan corresponding local times in various cities to find a good starting time on any given date.
https://www.timeanddate.com/worldclock/fixedform.html lets you create a reference lookup page for a starting time you have settled on.
By the way, don't assume consistency within a geographic region or within a country either. Did you know that Hawaii, Arizona, and the Navajo Indian Reservation do not observe DST? Neither does Puerto Rico. Did you know that the country of Australia includes locations with half-hour and quarter-hour time zones? Did you know that some areas in Labrador, Canada follow one time zone, while other areas in the same province use a different time?
Web collaboration knows no boundaries. It's your responsibility to be unambiguous about starting times for participants from all locations.