In a forum I was reading the other day someone posted this question:
Does Google automatically localize you by location? For example, if a searcher resides in LA. When I type in “car repairs”, will I get local LA results only? And this is regardless of whether I am logged into my gmail account or not.
My answer was:
Well, What happens is that if the user, for instance, types the phrase “car repairs” and he/she has the location set to a specific city (in this case I assume it’s Los Angeles), then she/he will be shown local results. Also, if somebody is using their mobile phone for such a query they will be shown the local results based on the GPS location for their phone.
Nonetheless, if they do not have any location set on their computer or the GPS deactivated in their phone, they will probably be shown national results. Yet, it is good to say that every now and then local results will be shown on a computer based on the IP address that it has if no location has been chosen.
I hope this helps.