Unreliable WiFi on MacBook: how can I measure how "unreliable" it is? My MacBook Pro (15-inch, 2018) has WiFi problems. It sometimes takes 30 seconds to connect, and even once connected the WiFi will occasionally lock up and have to reconnect. I've also seen hints that, even while apparently "connected", my connections will hiccup or slow way down.

I have AppleCare+, so I'll be calling them, but before I do I want to measure the extent of the problem. So: how can I measure the quality of a WiFi connection, preferably from the command line? (I'll set up a script to measure and log the results every 10 seconds.)
So, how can I measure the quality of a WiFi connection


Use Apple's built in WiFi Diagnostics

Hold the Option (Alt) key while clicking on the WiFi logo on the menu bar.  You'll be presented with two diagnostic options:


Create Diagnostic Report
Open Wireless Diagnostics


The Report is what you're going to want to submit to Apple.

There's an excellent support document, If your Mac doesn't connect to the Internet over Wi-Fi that goes into in depth detail.

You can also get signal quality information via the airport utility and measuring the SNR values via Terminal, but basically, you'll issue the command:

$ airport -I