Mozilla has big plans for its browser and among the a fleet new features expected to rain down on us this year is greater personalisation of the new tab
In the latest Mozilla Firefox 127 release simply do the following:
Go to about:config in a new tab
‘Accept Risk and Continue’
Search for browser.newtabpage.activity-stream.system.showWeather
It's a shame Mozilla hasn't added a way to put custom widgets in the New Tab Page. It's relatively inconsequential compared to the whole Mozilla situation, but in a perfect world, I think it would be nice to have.