I just visited the official Philippine government tourism web site at http://www.tourism.gov.ph and see on the opening page that the temperatures for various cities in the Philippines are given in degrees Celsius only. I tried going to other parts of the site to see if they give distances only in kilometers but Explorer crashed on me while loading what I think was a Flash image. (<begin rant> I wish they wouldn't bother with that stuff, especially for folks like me with a 56kps dialup line -- at least let me select a non-Flash version of the Web site! <end rant>)
Perhaps someone else with a more robust setup can poke around the site and see what's there. If it's all SI, then I presume that's the measurement system the government specifies officially over there. The other quick check would be the web site for whatever Togalog newspaper (is there one?) that is published in the Philippines. If stories there are written using only SI, then again I see that as evidence that everyday usage is likely to be SI. (Of course, I've seen it written on this list that the Toronto newspapers use SI only, but that doesn't mean that in everyday speech in Toronto one hears only SI! So my conclusion about the Philippines can't be guaranteed.) Ezra