@RickN I'm not sure. I'm in Australia, so time zones may come into it.
All I know is I rode 15km on Sunday before midday, then 7km this Monday morning. My week count says I've ridden 11km this week??? Which makes me think it kicked over into this week part way through my Sunday morning ride.
The cutover time would be somewhere 0hrs UTC/GMT.
Anyone else got any data to assist?