There is a new way to share the weather forecast in a new version of the Windy.app for iOS 11.2.1, from Aug 13, 2022. It was very easy before and still is, but it's one click faster.
All you have to do now is take a screenshot on your iPhone. At that moment a pop-up window will appear on which you will see a "Share" button and "Copy the link". At the same time, the screenshot will be saved in the Photos app on your iPhone.
Next, choose one of the available ways offered by Apple or copy the link in the message you're going to send to a friend to invite him/her/they to the spot.
As before, you can share the forecast by clicking on the three-dot icon to the right of the spot name on the spot screen.
Update the app in the Apple App Store.
Sharing weather forecast in the Windy.app for iOS
Sharing weather forecast in the Windy.app for iOS
Sharing weather forecast in the Windy.app for iOS