WiFi keeps dropping on iPad mini Retina

When I'm at home or a friend's house, the wifi eorks perfectly. However, in public areas that have wifi such as hotels or my college campus, the wifi only stays connected for roughly 5 seconds and then drops. I'm able to open up a webpage about 40-50% of the time before the WiFi bars on the top left disappear and i'm suddenly taken to a page that tells me to connect to the wifi. I have tried everything, including renewing leases, resetting network settings and restoring the iPad mini itself. Is this a problem that is common for the ipad mini retina? Or is this a problem that can be solved when trying to access public wifi? Please HELP!! this has been driving me crazy and really interfering with my schooling.