The timezone of Guernsey
Timezones are always computed by their difference to UTC, the "Universal Time Coordinated". In Guernsey exists only a single tonezone at UTC0. E.g. New York has the Eastern Standard Time at UTC-5 and the time difference between NY and Guernsey is 5 hours.
They have a nationwide clock change from standard time to daylight saving time, where the clocks are switched forward by 1 hour in summer.
The next clock change in Guernsey will be on October 25th, 2020 at 2:00 to standard time. Back to overview: Guernsey