A little of the basics on the Saratoga templates (forgive me Ken if I don't get any of this right!).
The CUtags.txt file that gets processed in Cumulus and sent to the website as CUtags.php replaces the Cumulus variable (e.g. <#TtempYL>) with its actual current value. At the bottom of the CUtags.php file, there is additional code which puts all the variables in the file into an ARRAY $WX[] thus using the form;
Yesterday's low temp was< ><?php echo $WX[TtempYL] ?>
uses the data item directly from the array.
However, if the relevant variable is also added to CU-defs.php (which is called by CUtags.php) then there will be a 'WD' variable $mintempyestt which is created by the line $mintempyestt = $WX['TtempYL']; in CU-defs.php.
Why $mintempyestt instead of TtempYL? Well the WD tag is %mintempyestt% not <#TtempYL> and the Saratoga template started with WD. So the XX-defs.php mechanism not only provides $vars for the webpages but also provides a 'translation' service so each different weather software system can be 'translated' to the common WD 'language' so the templates can work unchanged with multiple weather softwares (is softwares a valid word?).
So, you can see this is the process and format indicated in my previous post.
If you want to do any customising or creating new pages, then you will not get far without having the wiki pages from Cumulus explaining these variables (so you know what is available and how to apply them), along with a similar webpage from Saratoga and the CU-defs.php file at hand.
I have a local copy of the files from the Cumulus Wiki for realtime, webtags, and Dayfile (plus others) handy as references.
So Jachym, this is no more complicated than what you do and is the same process for all Saratoga template Weather software including meteobridge. It is just that you have done all the work yourself rather than utilising a ready-made solution. This may have suited you but for may of us without the coding skills to begin with, using a ready-made solution and working with it is a great way to get a website up and running , and to learn how to do it by making changes and adding pages to suit our personal preferences.