Acrylic WiFi Free is a free-for-personal-use wifi scanner which runs on Windows 7 and later.

The program identifies local wireless access points and devices and displays a table listing their details: SSID, MAC Address, Vendor, type, RSSI, channel, 802.11 (a/ b/ g/ n/ ac), security details (WEP/ WPA/ WPA2/ WPS), and when they were first and last seen.

In addition, a Signal Strength chart plots the strength of each signal over time, while "2.4GHz APs" and "5GHz APs" charts graphically show their channel usage.

A built-in Connectivity module can run brute-force testing on your chosen network against a sample dictionary of common passwords.

There's also an optional Monitor Mode which uses Acrylic's own driver to monitor network packets and may help you identify hidden networks.

A $47.99 (lifetime license) professional version takes the product further by displaying more information, generating reports, capturing data via airpcap and being able to work with pcap files, too.