Yep.. that's the way it's
supposed to work. It only gets the data for you and puts it into arrays for use with PHP printing.
Your script is returning (if you do a view-source on the page above)
<!-- get-UV-forecast-inc.php V1.02 - 03-Mar-2008 -->
<!-- UV forecast courtesy of and Copyright © KNMI/ESA (http://www.temis.nl/). Used with permission. -->
<!-- UV data load from from cache ./uv-forecast.txt -->
<!-- Date='29 Apr 2009', UV='4.2' DOW='Wednesday' YMD='20090429' -->
<!-- Date='30 Apr 2009', UV='4.2' DOW='Thursday' YMD='20090430' -->
<!-- Date='1 May 2009', UV='3.8' DOW='Friday' YMD='20090501' -->
<!-- Date='2 May 2009', UV='3.4' DOW='Saturday' YMD='20090502' -->
<!-- Date='3 May 2009', UV='3.1' DOW='Sunday' YMD='20090503' -->
<!-- Date='4 May 2009', UV='3.0' DOW='Monday' YMD='20090504' -->
<!-- Date='5 May 2009', UV='3.2' DOW='Tuesday' YMD='20090505' -->
<!-- Date='6 May 2009', UV='3.0' DOW='Wednesday' YMD='20090506' -->
<!-- Date='7 May 2009', UV='2.8' DOW='Thursday' YMD='20090507' -->
<!-- after date=20090430 processing, shifted 1 entries -->
<!-- Date='30 Apr 2009', UV='4.2' DOW='Thursday' YMD='20090430' -->
<!-- Date='1 May 2009', UV='3.8' DOW='Friday' YMD='20090501' -->
<!-- Date='2 May 2009', UV='3.4' DOW='Saturday' YMD='20090502' -->
<!-- Date='3 May 2009', UV='3.1' DOW='Sunday' YMD='20090503' -->
<!-- Date='4 May 2009', UV='3.0' DOW='Monday' YMD='20090504' -->
<!-- Date='5 May 2009', UV='3.2' DOW='Tuesday' YMD='20090505' -->
<!-- Date='6 May 2009', UV='3.0' DOW='Wednesday' YMD='20090506' -->
<!-- Date='7 May 2009', UV='2.8' DOW='Thursday' YMD='20090507' -->
so the cache is working.
To print the values you can see examples at
http://saratoga-weather.org/scripts-UVforecast.php#UVworld on how to use the script in your page.
Best regards,
Ken