Source

JKR's original site: The Watch

The wristwatch on the desktop is not clickable. It displays the current time according to your computer’s system. (If you reset your computer’s clock, it resets the time on the watch, and the day to night changes across the site.)

The marks around the face are that of a compass, not a clock. with 16 marks rather than 12… even though it is numbered with the four traditional quarter hours: 12-3-6-9.

watch - typical appearance

During Peeves‘ visit, the watch goes wacky.

It begins with bright blue lightning-like crackles.
watch - bright blue lightning-like crackles

Then the face glows turquoise blue.
watch - face glowing turquoise

Then small dots appear around the edges in place of the hour markings and 12 hands appear one at a time around the face.

watch - twelve hands appearing

The dots are slightly different sizes and colors (planets?), leading me to believe it is a representation of Dumbledore’s watch, which is described as having “12 hands but no numbers; instead, little planets move along the edge“.

watch - twelve hands

After the doxy flies through, the watch face emits a flash of white light and returns to normal.

watch - flash of white light

JKR's original site: The Watch
Abbreviation JKR's original site: The Watch

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The Harry Potter Canon