it looks like the premium I purchased on the IOS will work on the Mac desktop.
Dear users,
in case you are having issues activating your Windy Premium subscription, please follow the steps below.
Note that purchase needs to be restored on the platform, where is it was purchased, e.g. you will not be able to restore Premium on mobile phone (in-app), if it was purchased on desktop (via FastSpring), but you will have to restore on desktop as well.
Furthermore, purchasing Windy Premium will give you access to Premium features on all platforms (desktop, Android and iOS), you do not need to purchase separately for each platform.