Of course ephem is installed, thanks. And, yes, you are right with your conclusion. So I am missing $sun_visible_change.
My top of celestical.inc looks like:
## If extended almanac information is available, do extra calculations.
#if $almanac.hasExtras
#set $sun_altitude = $almanac.sun.alt
#if $sun_altitude < 0
#set $sun_None="<i>(Always down)</i>"
#set $daylight_str = "00:00"
#else
#set $sun_None="<i>(Always up)</i>"
#set $daylight_str = "24:00"
#end if
#set $sunrise_ts = $almanac.sun.rise.raw
#set $sunset_ts = $almanac.sun.set.raw
#if $sunrise_ts and $sunset_ts
#set $now = $current.dateTime.raw
#set $today_daylight = $sunset_ts - $sunrise_ts
#set $seconds = $today_daylight
#set $hours = $seconds //3600
#set $seconds %= 3600
#set $minutes = $seconds//60
#set $seconds %= 60
#set $daylight_str = "%d Stunden, %d Minuten, %d Sekunden" % ($hours, $minutes, $seconds)
#set $yesterday = $now - 24*3600
#set $yesterday_daylight = $almanac($almanac_time=$yesterday).sun.set.raw - $almanac($almanac_time=$yesterday).sun.rise.raw
#set $difference = $today_daylight - $yesterday_daylight
#if $difference
#set $delta = abs($difference)
#set $amt_str = "%s%d Sekunden" % (str(int($delta) // 60) + ' Minuten, ' if ($delta // 60) > 0 else '', $delta % 60 if ($delta // 60) > 0 else $delta)
#if $difference > 0
#set $delta_str = "%s mehr als gestern" % $amt_str
#else
#set $delta_str = "%s weniger als gestern" % $amt_str
#end if
#set $daylight_str = "%s<br/>%s" % ($daylight_str, $delta_str)
#end if
#end if
#end ifI am still in my own german translation version. I maintain this since many years and don't dare to replace it strictly. That is also, because I use
https://github.com/gedger/alltimeSeasons instead of the original Seasons skin, which also needed to be translated. So, I do not update Weewx very often, because I always have to diff most of the files changed. Which sometimes is not as completely adopted as it should. As you can see here.
The text you mentioned is much shorter in celestial.inc.tmpl-dist, which should be the correct version, I think. I must confess, that I have ignored it.
So, where should I insert or replace your insert?
BTW, In sunmoon.inc, there is also a $daylight_str.
<div id="sunmoon_widget" class="widget">
...
<div class="widget_contents">
<div id="celestial_summary">
...
<td class="label">Tageslicht</td>
<td class="data">$daylight_str</td>
It looks like 17:05 now. May be, there is also a change needed? The diff with the new version does not tell any differences.
Peter