The Best Time Of Day For Focus And Peak Mental Performance

So I just finished analyzing 6000+ chess games to find out when out when my peak performance is. Chess is essentially an entirely mental endeavor, so it would stand to reason that chess performance is highly connected to general focus and brain processing speed. So by analyzing my games, I am able to extrapolate that and determine the time of day where I have peak mental performance

I'll skip the technical details, but here's a plot of my effective rating (practical playing strength), subtracted by my actual rating:

All dots that are above 0, indicate that I'm playing better than usual. Everything below 0 indicate that I am playing worse. First thing to note, is that time of day is not a strong predictor of playing strength. But we can still add a trendline through polynomial regression:

Technically, the R-Squared is about 0.07. My peak playing strength is right around 15:00 (3PM). My worst time of day is apparently as soon as I wake up, around 07:00 (7AM). Also my performance takes a dip after 21:00 (9PM), but the more interesting part is that my performance becomes significantly more inconsistent late at night. Both my best and worst rating performances are right around midnight, and by a longshot.

In terms of scale, the trendline suggests that there really isn't a big difference in mental performance throughout the day. The difference between absolute peak performance and the worst time of day is about 65 rating points. Of course, that's not a meaningless number. But considering that I've gained around 500 points in the last few years suggests that mental ability is far more important than time of day. My 7AM self would destroy my 3PM self from 4 years ago - and it wouldn't even be close.

In conclusion: practice matters far more than trying to find your best time of day.