What is the wavy graph in weather forecast showing?

[Surinova]

What does the wavy graph which is going in background of the rain forecat, temperature, the little sun and clouds icons and the time means? It usually gray, with some pink and light blue when high.

[Gkikas LGPZ]

@surinova
If you mean this grey line .... it's presure
https://community.windy.com/topic/5145/metegram-unknown-line