I routinely minify my bloated 'ajaxWDwx3.js' in order to speed page loads. One thing to keep in mind though is that you need an uncompressed copy for editing of this particular file since it contains some settings. The easiest site for me to use is
this online javascript compressor.
An alternative scheme would be to save the compressed file as 'ajaxWDwx3-min.js' or some such and reference this as
$SITE['ajaxScript'] = 'ajaxWDwx3-min.js'; // for AJAX enabled display
in 'Settings-weather.php'.