Browser time is one hour behind

it might have been enabled by an addon. The manual steps are listed in Resist Fingerprinting — that one would nonetheless show the time zone as UTC/Iceland, one hour behind if you're around GMT/CET/Europe — if you're somewhere else, that won't be the culprit.

it might have been enabled by an addon. The manual steps are listed in Resist Fingerprinting — that one would nonetheless show the time zone as UTC/Iceland, one hour behind if you're around GMT/CET/Europe — if you're somewhere else, that won't be the culprit.

I don't have any addons installed and I live in Alberta. If I had to guess, somehow Daylight Savings caused it even though we don't do that anymore.

Right. That depends on what the underlying OS uses. If you're on the latest Windows update, then it's tracked in https://bugzilla.mozilla.org/show_bug.cgi?id=2082211

Ok so, guess I just gotta wait then?

I don't understand the issue enough — the bug timeline shows some upstream Unicode updates, some mapping, heuristics etc. are in https://bugzilla.mozilla.org/show_bug.cgi?id=2058419 mainly for the DST change — I however am not sure if this later one is only relevant when the Windows auto–detection is disabled and a time zone is picked manually… or that doesn't affect it.

A workaround might be disabling auto–detection in Windows and setting a time zone that matches yours, but had the rules in place for some time already, to have it mapped correctly.

Or, yes, just wait. I think the new time zones ship next week in 159, this 1hr difference in system mapping might ship in 159 or 160 later in November.

The windows system time is correct. The timestamp on emails when I open Gmail in Firefox is behind by 1 hour. NB - Gmail on my Android phone has the correct time. This tells me it is likely a Firefox issue.

Yes, the new Windows names of the time zones https://windowsforum.com/news/windows-time-zone-updates-for-bc-alberta-and-morocco-november-2026-admin-guide.446063/ are not known to existing Firefox versions so the patches linked earlier track that. This blog post has workarounds. (I'd switch to an alternative region like Yukon or Saskatchewan based on where you're located for time being to see if that resolves the difference for now.)