I'm not sure if this is even possible in Google Analytics. Is there a way to find out the maximum number of visitors that visited a site within a time period of one minute, or one hour? Or is the data only available per day.
I just checked and this is now available
Public Beta is now available. Sign-up to be whitelisted. http://analytics.blogspot.com/2013/08/google-analytics-launches-real-time-api.html https://developers.google.com/analytics/devguides/reporting/realtime/v3/