@vsinceac Thank you for your reply.
But I already read that. Legends or humidity numbers regarding to gray levels are not described in that article.
I hope anyone of windy developer explain this.
I'm using Windy for check wather and wind informatio during flight.
It's most useful weather information tools in the world.
If Windy can show more layers like airspace regions or Flight InformationRegion, it's very useful to pilots or relevant to flight,
Please consider it.