A 7 × 24 grid below the breakdowns: days down, hours across. Darker means busier.
Whose clock
Hours are in your browser's timezone — the same clock every other chart on the dashboard uses — not the visitor's local time.
A site with readers across several continents will see that spread flattened into your clock, and that is the honest way to show it: the grid answers "when should I publish" for you, not "what time was it for them".
Read it over a long range
The grid follows the date range above it, so a seven-day range gives one observation per cell and a ninety-day range gives about thirteen.
On a short range the pattern is mostly noise. A single busy Tuesday afternoon looks like a habit when it is one afternoon. Widen the range before reading anything into it.
What it is good for
Publishing and sending. The hours that are already busy are the hours people are already looking.
Spotting a schedule that is not yours. A block at 03:00 local usually means automated traffic rather than readers — cross-check it against AI crawlers.
Seeing a week that is not a work week. A consumer site and a B2B tool produce visibly different grids, and the difference tells you which one you are running.
Related: Traffic quality by channel.