It’s not free but it’s a damn good app and will do what you want and so much more. The part I like the most is that it doesn’t just show signal strength but it also shows noise and SNR. Super helpful.
https://apps.apple.com/ca/app/wifi-explorer-scanner/id494803304?mt=12
When you are writing the date, the only correct way is ISO8601 (YYYY-MM-DD). If you’re speaking to someone (verbal communication) then do whatever you want.