Download the mod, extract it and copy the content to you Asseto Corsa folder.
This mod includes a weather, a ppfilter and a ReShade.
I created this mod specially for Nordschleife but you can use it in any track. To get the Nordschleife look on the screenshots above you need to install two more mods, Winter Nords 1.0 from http://www.racedepartment.com/downloads/winter-nords-mod-sliding-ice-asphalt.13924/ and Wet Nordschleife from http://www.racedepartment.com/downloads/wet-nordschleife.14832/
This mod must be run from Content Manager to correctly load the clouds. From Content Manager you must select the "Winter night" weather and the "Winter night" ppfilter.