A store’s opening hours will probably remain 9am-5pm regardless of any time zone changes around it. If you run a bunch of stores across time zones you need to know where each store is and whether it’s summer or winter to work backwards to find out 9-5 in UTC.

Every heard of daylight savings time (DST)?

Can be adjust client-side, or wherever you need to present it, rather than adjusting stored data.

This is only sometimes true. Cases like opening hours and daily batch processing rely on local time. Persisting the values in UTC mean best case you are wrong half of the year and worst case all of it.

Just because you're storing the time in UTC doesnt mean you can't also store the timezone, and lots of other related data too.

6am in my time zone is two different times in UTC. Right now it is 14:00 UTC. But when DST starts it will be 13:00. So what UTC value do you insert into your database for the opening time of the coffee shop? And how do you convert?

Seems like the ideal way to store them to me!

Have you thought about this? How do you store shop hours in UTC for shops in timezones with DST?

Then you would be wrong, because they open at 9am local time - if the government changes local time with 2 days notice then opening time changes.

The coffee shop in my neighborhood is open from 6am to 2pm Pacific. We observe daylight saving time. The shop hours do not change. So, what UTC value do you store?

I guess it would change based on local time changes.