The situation: I have an all day event and want to be reminded by SMS at 8:00 PM the day before so I don’t forget.
The problem: According to Google Calendar, an “all day event” starts at 5:00 PM on the day preceding the event. Here’s the proof:
- All day event scheduled on Day X, reminder set for 7 hours before. Reminder received on Day X-1 at 10:00 AM.
- All day event scheduled on Day X, reminder set for 10 hours before. Reminder received on Day X-1 at 7:00 AM.
This effects both email and SMS reminders. One would assume that, logically, an “all day” event would start at 12:00 AM. So when setting the reminder time for an all day event, I have to subtract 8 hours. This limits reminders to only being sent until 5:00 PM. And this is true, I have tested it by scheduling a reminder “0 hours” before an all day event. I received it at 5:00 PM the day before.
And before you ask, YES I have set my timezone to GMT +10 in Google Calendar.
Solution? Change timezone to GMT +2? I’m just setting them to 0 hours now I can live with having reminders at 5.00 PM. But it doesn’t work right. They should fix it.

Just out of curiosity are you still receiving SMS reminders?
if so are you with Telstra?
looks like there is an issue with SMS reminders not being sent/received, post 1 FEB, not sure if its a Google or Telstra problem…
Yes, and with Optus.
I’m having the same problem with my reminders. I have my time zone set correctly to Central Time(GMT -6) in Google Calendar, but it appears that all of the reminders are being sent out based on GMT!
If I have an all day event, and have a reminder set to send at 1 hour before the event, I get an email at 5pm (11:00pm GMT)!
This is really frustrating, but I can’t find a way to fix it in Google Calendar.