You must remember that it can be anywhere from your pc to any of the machines/network thru which traffic has to travel to get to this or any other site. There are tools available to give you a better indication when a pageis slow where the problem lies. I'll work up a post on easy ways to do this when I get a minute.
In the meantime, for bigger sites etc there is downdetector.com that will show you the number of reported issues for some major sites and ISP's (spectrum, AT&T, Verizon etc)