In many countries there is a summertime and wintertime difference. Especially when you have a presentation early in the morning the day after the change to summertime, you may want to point out the summertime if you are planning to send a reminder before your presentation. Your audience may appreciate such warning.
If people forget about the summertime they may arrive an hour too late (especially when you have the presentation first thing in the morning).
The change to wintertime is less of a problem as those who forget about it will arrive an hour to early. In that case you just need to make sure that the know it is not due to cancellation of your presentation that the presentation didn’t got started.