Twice? I wonder what alarm clock apps decide for this.
GNU date defaults to EDT, but adding the local time zone name can give the other time:
date --utc --date='TZ="America/New_York" 2025-11-02 01:30:00'
Sun 02 Nov 2025 05:30:00 UTC
(Which is 01:30 EDT)
date --utc --date='TZ="America/New_York" 2025-11-02 01:30:00 EST'
Sun 02 Nov 2025 06:30:00
although for London it defaults to GMT: date --utc --date='TZ="Etc/London" 2025-10-26 01:30:00'
Sun 26 Oct 2025 01:30:00 UTC
date --utc --date='TZ="Etc/London" 2025-10-26 01:30:00 BST'
Sun 26 Oct 2025 00:30:00 BST
It throws an error the other way: date --utc --date='TZ="Europe/London" 2025-03-30 01:30:00'
date: invalid date ‘TZ="Europe/London" 2025-03-30 01:30:00’
