how to get cpu temp on menu bar

FWIW, I use iStat Menus to display CPU temperature on my Macs' menubars.

AFAIK, there is no simple way to do this natively with macOS, whereas it may be possible as I have done so with Linux & Raspberry Pi OS and wrote either Python or Shell scripts for this. Just haven't had a need to do so with my Macs since I use iStat Menus.

A few temperature gauges I've seen and also use

on an older Mac mini with dual-drives + 4 cores is

"Macs Fan Control" gives me options by default..

As your newer MacBook Air probably hasn't a Fan

since those evolved past need for one; not sure if

any other recent changes to 'Macs controls' exist.

..An easily removed item, if you venture to test it..

Some options now list MacBook/Air among others:

https://crystalidea.com/?source=fancontrol_mac

https://crystalidea.com/macs-fan-control/fan-presets

[By custom default seems it may monitor CPU temps.]

CPU temp on the menubar is not a built-in feature of macOS. It is provided by a third-party application that provides a menus extra feature to put that information on the menu bar.

I think it is a waste of time as there is nothing you can do about CPU temperature unless it is to stop playing a game or attempting to run a virtual machine guest on an under-configured Mac. If the CPU gets too hot, the Mac will throttle it or shut the Mac down to cool it.

Do you stare at the tachometer in your car, or do you just instinctively avoid over-revving it? I have a heads-up display in my car and it is configured to just show the digital speed which has reprogrammed me from continuously looking down at the speedometer and tachometer.