How to present time of a repeating event happening in country with DST?

Question

I am doing a livestream on given weekdays at 21:00 Polish Time. Polish Time does not mean much to anyone outside Poland and, as far as I know, there is no specific and universal designation for this time zone including the fact that it depends on daylight saving time.

Right now we are in GMT+2 which is soon going to change and I am not going to remember to change the description.

How can I clearly and easily present to visitors that something happens regularly at 21:00, GMT+1/GMT+2, depending on DST?

Answer 1

Daylight Saving Time is, in some cases, signified by different labels depending on the time of year. For example, Daylight Saving Time in The United States uses the following:

Time Zone                  Standard Time  Daylight Saving Time
Eastern Time Zone          EST (UTC-5)    EDT (UTC-4)
Central Time Zone          CST (UTC-6)    CDT (UTC-5)
Mountain Time Zone         MST (UTC-7)    MDT (UTC-6)
Pacific Time Zone          PST (UTC-8)    PDT (UTC-7)
Alaska Time Zone           AKST (UTC-9)   AKDT (UTC-8)
Hawaii–Aleutian Time Zone  HAST (UTC-10)  HADT (UTC-9)

Thus you can indicate that a particular event happens at 1PM EST / 2PM EDT. But, you really shouldn't.

... and I am not going to remember to change the description.

What you are doing is putting the burden of memory on your users. You're making the users do the work because you don't want to. Be it a notification in your reminder app, or a little extra code to automatically flip the date, it should not be your user's responsibility remember if it is currently +1 or +2.

User Experience is about their experience. It is about taking the extra step to ensure that your have externalized the memory requirements of your users. They shouldn't have to remember, they should just be able to look at their watch and know when to arrive.

Answer 2

First, in some cases GMT is incorrectly assumed to mean UTC plus British daylight savings. The takeaway is that you shouldn't use GMT at all, use UTC instead.

Second, Polish time is CET, Central European Time, which means something to a couple hundred million people outside of Poland.

What matters to your users isn't if the stream takes place at UTC+1 or UTC+2, they care when the stream takes place in their time. They can figure that out easily by googling "21:00 CET", which will translate the time to their timezone. Just place a link to that google search.

In addition, you should mention in the livestream that next episode will be affected by daylight savings. You can do this by putting a calendar alert that reminds you ahead of time.