It shows end of the day, whatever that is. I assume the end of the day uses some reference time zone. Otherwise if you changed to a different time zone, the entire graph would need to be recalculated.
Lichess, for example, has a day based on GMT, I believe. I've not notices on chess-com.
Question about rating graphs
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Jan 15, 2026
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#2
what about this though because it doesn't display a rating drop
Jan 15, 2026
0
#6
ChanMan4 wrote:
what about this though because it doesn't display a rating drop
Those graphs display the highest rating attained in the day.
So, when looking at my rating graph on my profile, it doesn't show the true rating changes. For example, yesterday I dropped from 2072 to 2044, but it doesn't show that, it just shows my rating ent from 2072 to 2073. Why is this?