YES! The times are currently a complete mess

+1 Was going to request this feature myself in case no one else had yet.

I don't want to use settings of my region. USA resident but use 24 hour format always and European date format sometimes. Should be able to choose what formats we want to use

24 hour format easier to use

I'm missing the the possibility to set appointment times to minutes.. I use that a lot for my work schedule. Would be great if that could be added thanks.

ISO 8601 or bust

Yes please!
ISO 8601 is the way to go.

Please!

As an American, I wish this were already a thing!

Yes, non-american here.

Yes please!!!

Yes please! I would love to use my native date and time format.

Yes!

Please add options for ISO 8601 and 24-hour time. My regional settings are already set this way, but the flexibility of defaulting to the client's regional settings and allowing overrides to other common formats would be ideal.

This uservoice item refers to ProtonMail, but the options should be available across the Proton suite:
https://protonmail.uservoice.com/forums/284483-feedback/suggestions/7158457-option-to-change-the-format-for-email-dates-and-ti

Please add options for ISO 8601 and 24-hour time. My regional settings are already set this way, but the flexibility of defaulting to the client's regional settings and allowing overrides to other common formats would be ideal.

This uservoice item refers to ProtonCalendar, but date and time settings should apply across the Proton suite:
https://protonmail.uservoice.com/forums/284483-feedback/suggestions/41638129-calendar-time-option-for-24-hour-format

An option under General to choose a time display default, between AM/PM and 24H formats.

+1. While I live in Australia, I would prefer the ISO format YYYY-MM-DD myself. Thanks !

This is must. American format is confusing and unproductive.

+100

+1