I'm on pacific time and the events are at 6 am (gold) until 9 am, 9:30 am (gold) until 12::30 PM, 1 PM (platinum) until 8PM, 8:30 PM (gold) until 11:30 PM, and I think there is another at midnight but I dont stay up that late usually, I may have done it a couple of times. I think there is one more that ends at 5:45 am because when I first log in when I wake up it is almost over. Good luck!
Yes, there is another event that starts at midnight Pacific. I believe there is one more that starts sometime around 3 a.m. Pacific. Basically, there is a half-hour break between each event, so no matter when you open the app, you'll either be in a current event or in the half-hour waiting period between events. If you open the app and it says the start of the next event is more than 30 minutes, force closing the app and opening it again will reset the timer and show the correct amount of time to the next event or the amount of time left in the current event.
The events overnight (at least for Canada and US) go from 12 - 2:45 am Pacific and 3 - 5:45 am Pacific. There is only a 15 minute gap for these ones.