Google Webmaster "Average Position" makes no sense!

[Bishop]

I have an average position of 5-7 for several of my top keywords according to Search Queries in Google Webmaster. But I never see my site in those position when I look the site up. I know this is a site average, but to never see the site in those positions is perplexing.

Can anyone shed some light on why "average position" does not coincide with serp?

 

[Linda Buquet]

I'm just guessing here...

Searcher location, mobile close by, personalization could all cause others to see you even if you don't?