[blahedo]

It's worse than this: it's not just "what's my (app developer) reference frame for time in this app" but rather "what is the user's reference frame", and that is a thing that changes even for a single user.

I have been in a paper-notebook-calendar mode for a while now, but every time I've dealt with an electronic calendar app, it's been a struggle, because sometimes I write down a time relative to the time zone I'm in right now, and sometimes I write down a time relative to the TZ I'll be in when the thing happens (on vacation, at a conference, whatever). And for things in the latter category, I _want_ to visibly see the local-to-the-event time so that I can talk to other people about it, but I also want it to be in the correct time when I'm actually at the event so that I don't miss an appointment. This is trivially easy on a paper calendar I keep for myself and is Really Dang Tricky for electronic calendar apps.

[afiori]

The issue here is that timezone are often handled like an environment setting instead of as an element of the day-time-timezone tuple

[esseph]

I use Google for some things.

One of the things you can do with Google calendar is have multiple timezones listed on your calendar. This way, it's easy to see when the even is regardless of what time zone is the source of reference. It's a lifesaver.

Note: This seems to work on Google Calendar web, but I can't find a way to do this with the mobile app (Android).

[SenHeng]

I've used the default Calendar app on my iDevices since forever and it has always done the timezone conversions auto-magically for me. The only extra bit of work I have to do is convert the date to my local time zone during input.