Google results fluctuating throughout the day?

[paymatters]

Has anyone else noticed they rank higher in the evening than they do say in the morning?!

Was just wondering if this is something deliberate google do. Was wondering if it may be dictated by your hours of opening listed on google??

Or is it just that the sites around the one I'm looking at are so similar ranking that small fluctuations mean listing positions are always changing??

Or is it that I use a variety of devices and locations to search throughout the day.