When your page first loads, it is PHP (and the settings inside of Settings.php) that determines how the date/time is put in the HTML of the page returned to the browser. After the page is loaded, the ajaxWCTwx.js JavaScript begins execution in the browser, reads the WCT_realtime.txt, and rewrites parts of the HTML page by replacing contents of the <span class="ajax" id="..."></span> pairs.
The ajaxWCTwx.js has only limited formatting capabilities for date.. mainly whether to display the date as dd/mm/yyyy or mm/dd/yyyy format - the dd-MON-yyyy format is not available in the JavaScript.
I suggest you settle on dd/mm/yyyy or mm/dd/yyyy format for your date format both in PHP and the Javascript.. then the change when the JavaScript begins execution will just be a 'green flash' of the characters.
The time format is flexible in PHP, but again, the JavaScript simply presents the contents of the second field in WCT_realtime.txt, so those contents are determined by WeatherCat template for WCT_realtime.txt .. no additional formatting is available in the JavaScript.
Currently, the WeatherCat tags used in the WCT_realtime.txt template are:
de$|t24s$|
for the first two fields.
Hope this helps...
Best regards,
Ken