A Shared Outlook calendar shows wrong timezone in Google calendar.

Google points the finger at MS in this case. This issue on the google forums has this posted:

"I've run some tests and it seems your problem is in fact the TZID that Outlook is using: DTSTART;TZID=Central Europe Standard Time:20240120T090000The TZID "Central Europe Standard Time" is not on the official list:https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#Time_Zone_abbreviations

The correct TZID (for me) is "Europe/Paris"."

I wrote a small proxy app that fetches my Outlook calendar, replaces all instances of "Central Europe Standard Time" and "Romance Standard Time" with the corresponding (and standard) TZID "Europe/Paris", then serves it as a .ics to Google Calendar, but it didn't look any different next to the events from the original Outlook calendar. Maybe I'm missing something? Or maybe the calendar defines arbitrary timezones in the vcal headers and the names don't matter?

Either way, while you might be onto something, subscribing to the original Outlook URL in Apple Calendar and the macOS Fantastical app both result in displaying the events at the correct time, so I'd venture out and say Google Calendar is at fault here.

Google points the finger at MS in this case. This issue on the google forums has this posted:

"I've run some tests and it seems your problem is in fact the TZID that Outlook is using: DTSTART;TZID=Central Europe Standard Time:20240120T090000The TZID "Central Europe Standard Time" is not on the official list:https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#Time_Zone_abbreviations

The correct TZID (for me) is "Europe/Paris"."

did not change it for me

the Exchange ics does contain TZ data.

the question is now who doesn't adhere to the standard? MS or Google? I'd say Google has the better track history, but I did not check it in this case

BEGIN:VCALENDAR 

METHOD:PUBLISH 

PRODID:Microsoft Exchange Server 2010 

VERSION:2.0 

X-WR-CALNAME:Calendar 

BEGIN:VTIMEZONE 

TZID:W. Europe Standard Time 

BEGIN:STANDARD 

DTSTART:16010101T030000 

TZOFFSETFROM:+0200 

TZOFFSETTO:+0100 

RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10 

END:STANDARD 

BEGIN:DAYLIGHT 

DTSTART:16010101T020000 

TZOFFSETFROM:+0100 

TZOFFSETTO:+0200 

RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3 

END:DAYLIGHT 

END:VTIMEZONE 

BEGIN:VTIMEZONE 

TZID:Greenwich Standard Time 

BEGIN:STANDARD 

DTSTART:16010101T000000 

TZOFFSETFROM:+0000 

TZOFFSETTO:+0000 

END:STANDARD 

BEGIN:DAYLIGHT 

DTSTART:16010101T000000 

TZOFFSETFROM:+0000 

TZOFFSETTO:+0000 

END:DAYLIGHT 

END:VTIMEZONE 

BEGIN:VEVENT

Didn't fix it for me either 😢

OK, so some of you are finding help with that OutlookGoogleCalendarSync tool and I'm really happy for you.

That doesn't change the fact that those of us who are working in a Mac ecosystem and trying to manage the complexities of certain Outlook-only clients and other Google-only clients don't have a solution.
In other words, if I've got a Mac I can't get around this silly time-zone-greyed-out issue...

Google... Microsoft... whoever - this is disappointing. You have some of the most brilliant coding minds in your employ and you're leaving us stuck without a solution.