Then accept that UTC is a timezone and just use that everywhere. There are also a lot of things that can’t be easily stored in UTC, like opening hours.
Here, I'm not even sure what your point is. A datetime object cannot capture a range, no, just like a number can't capture a range of values. But through the magic of having two of them, we can get easily create a data structure containing two datetimes to represent a range. 5pm is not a vague concept, it is the time 5pm, the hour that typically comes after 4pm and before 6pm. If your point is that you can't store only a time in a datetime object, that's true, that's why the standard library also provides the `time` object which represents a time.
Where things might get a bit more complex is if you want to store the time of a recurring event that should occur at the same time on multiple days for a given timezone. In this situation, you can typically use a naive time object to represent a wall clock time, plus the timezone that the user has requested. This way you still have all the raw information to decide when the event will happen in the future. (Note however, that the same time can occur multiple times on the same day, for example during daylight savings changes.)
And you're totally right about `time` existing, it slipped my mind that time has a tzinfo slot. I do think you should still take care and I would avoid having any naive time objects just floating around beyond the serialization layer though.
The key here is that the timezone info includes the daylight/standard designation. Or, in the ISO format -4:00 or -5:00 from UTC.
I think you meant to put ET (Eastern Time), which is still 9:30AM, but without a date associated with that time, there's no way to convert that to UTC or other timezones that don't have the same daylight saving time schedule.
So, when possible, it's best to store (future) human events in a localized datetime string. For things like physical events, the opposite is true of course - you can't say what will be the local date and time when the Sun will hit high noon over Athens 10 years from now, but you can certainly calculate the UTC timestamp for that.
Yes, you can store additional information to decipher the meaning of a UTC time but why? Storing locale is good because sometimes you need to know where something is, such as when converting the local time to another zone. But you should avoid creating dependencies between these values because it makes using them individually harder.
The coffee shop opens at 6am. That is an unambiguous fact. The coffee shop is in Seattle, WA. That is another unambiguous fact.
If the time is in UTC then you need to know the date the time was set or store a dtc flag and then build some logic to convert. You can just feed local time+locale into any datetime library and get whatever you need.
UTC is great for a lot of things. Such as recording when something happened. But local time has a place as well.