Say I'm connected to a particular access point and that I'm using Windows 10 Pro. How would I be able to find out if the access point is using 2.4GHz or 5GHz?
In windows 10 (once you connect) you just go to Settings/Netowrk&Internet/click on the SSID name and scroll down to properties. It tells you the Band, protocol, channel, security type, and all that good stuff.
update: Only on windows 10 anniversary update and up
on windows commandline:
netsh wlan show interfaces
See Radio Type and Channel
Windows 10 Home:
Network settings> wifi> advanced options
System information> Components> Network> Adapter> scroll down to wireless section