Still a great add-on! In new version -as many others- I miss the multiple days view. But I understand that Firefox will not be the same after v57. And as some other add-ons I have (i.e. Wired-Marker), all will change to follow the new API of Firefox. The Forecastfox as well.
I have to learn a new habit, to click on the Forecastfox button. Then everything is better than before.