I am experiencing exactly the same thing...
//$pos = strpos($data, 'yweather:location');
$pos = strpos($data, 'yweather:CAXX0664');
$attr = explode('"', substr($data, $pos, strpos($data, '/>', $pos)-$pos));
//$ret[0]['location'] = $attr[1].', '.$attr[3].', '.$attr[5];
$ret[0]['CAXX0664'] = $attr[1].', '.$attr[3].', '.$attr[5];
In the admin interface I enter "CAXX0664" (without quotes) where I would have otherwise entered the zip code. I have left the temperature scale at Farenheit, and I have changed it to Celcius with the same results; those being a blank page with the following source code:
<script type="text/javascript">//<![CDATA[
document.write('<link href="
http://joomsnap.localhost//modules/mod_s5_weather/s5_weather/style.css" rel="stylesheet" type="text/css" media="screen" />');
//]]></script>
So I conclude that this has repercussions into mod_s5_weather.php. The domain printed above is a site I have set up on my machine for testing purposes. I went ahead and removed the extra slash that was getting into the href attribute in mod_s5_weather.php. I didn't really think that would solve the problem, but I hoped...
My pessimistic side once again proved to be correct.
So now I'm here typing this message to implore anyone for any insight they might offer to the rest of the world. Like those savage Canadians to the north.