Why is IPv6 adoption higher at weekends?

Solution 1:

tl;dr: Because Comcast.

Comcast has, by any measure, the largest IPv6 deployment in the world, with the greatest number of users. Commercial/business networks are lagging behind with regards to IPv6. People are not at work on the weekends and such we see higher IPv6 adoption then. I'm sure other residential ISPs contribute to this trend as well.

Say what you want about Comcast's business practices. No one can fault them for being a staunch IPv6 advocate from very early on. (of course they were forced into it due to IPv4 not having enough addresses for them to manage their own device pool)

Solution 2:

Some mobile networks have already switched a large portion of their customer base over to IPv6 (T-Mobile being one that comes to mind).

If we make the plausible assumption that people tend to spend more time away from their home computers on weekends, then it makes sense that IPv6 traffic would increase proportionally.