We did mornings for the longest time. Then my parents decided to do midnight mass, and set the presents out while me and my siblings were in the car. When we got back it was an end run into the living room to see if Santa came while we were out. Became nights ever since then.
I know that was still, technically, morning, but it became the night before for many presents, and they still hid some to come from Santa for the day, after that.
Now it's kind of whenever we can all get together.