I have the Belchertown skin theme set to "auto" so it switches over to the dark theme around sunset.
I have noted that the Belchertown skin switches over to the dark theme at large fractions of an hour before sunset actually occurs.
Then, I got a report from a friend in the Eastern time zone, that the webpage theme switched to dark around 6:00pm Eastern time - around 2 hours early compared to the local sundown time (7:39pm Central) at my weewx weather station.
He said he had not clicked the manual theme switch at the upper right corner of the Belchertown page.
So, I started looking through the code to see how the theme change gets triggered.
Around line 507 the current hour and minute get assigned to variables with the expressions
var nowHour = d.getHours(); var nowMinutes = d.getMinutes();
Where is the time being read from?
1. from the clock of the computer that weewx is running inside?
2. from the clock of webpage visitor's computer?