@Green-Bean Right there is no way to customize the color scale on the App. You have to do it on the website www.windy.com, on desktop/laptop. On iPad it is possible if you use your browser with www.windy.com See screenshot of my iPad with color scale settings page

I've customize this color scale based on wind force and hurricane scales. Red is used for tropical storm/gale force winds, as the winds are dangerous enough to produce certain damages. Light white/purple indicates hurricane force winds (Category 1), and grey is used for major hurricane (Category 3). Dark blue indicates winds for jet stream and other extremely rare winds.

@siim I'm guessing you don't have an icm color profile installed and active in your system, changing the settings alone without installing an icm color profile doesn't cause the problem. @Korina I understand your limitations. Thank you anyway for taking the time to respond. Maybe natural development of software will end up fixing it. Greetings