php and shtml

Hello,

I am using the weather hack. I SSI it in my shtml front page, and it works fine. Whenever member updates city, front page shtml reflects change too.

I try to include that weather in a php page. It displays, but stays on the default only, not reflecting any changes. I tried
include (/path/to/weather.php) and the page will stop opening at that point.
I tried
include (http:/www.page.com/to/weather.php) and page opens but weather is not updating. Remains at default.

What am doing wrong?
Thanks.