DebugBear lets you monitor your website from one of the following regions:
The farther the test server or your users are from the server that hosts your website, the longer it will take to load your site.
For example, let's assume you host your website is hosted in New York and the user is in London. One request round trip from London to New York takes around 70ms. Establishing a connection to your server usually requires 3 round trips, so in the ideal case it would take 210ms to load your page.
The ping time for Sydney to New York is ~270ms, so a user in Sydney would have to wait at least 810ms for your page to load. Your site will show different performance characteristics depending on where your users are.
These are optimistic assumptions that assume a single request is all it takes to load your site. They also don't consider that, on a 3G connection, each roundtrip requires another ~150ms.
To solve this, host your website near where your users are. That's easy if they are all in one place, but harder if they are scattered around the world.
It might not be viable to host your application server in multiple locations, but one easy step to improve performance is using a globally distributed Content Delivery Network (CDN).