Hi Windy team,
a lot of people from sailing or outdoor sports using a lot pressure charts to be warned for changing weather. At the moment there is no Apple Watch App that can provide such a chart on a watch face. So that could be a simple but unique thing for your App (which I love, btw).
Here is a very good example for such a chart on a watch (example from Garmin Fenix):
Would love to see such a chart in future versions!