Hello, I have the same problem as JoeAMGC63: no winter atmosphere and no ice on the road.
The installation:
SteamApps/common/assettocorsa/Winter Nords Mod 1.0 by JW mods/content , mods , jsgme.exe , jsgme.ini
I launch jsgme.exe and I activate " winter the North 1.0" which passes to the right in the window. I launch AC, choose a car and the circuit nordschleife but no winter.
Thank you for your help and excuse my mistakes
Open the downloaded *.rar file. Doubleklick on "Winter Nords Mod 1.0 by JW". In there you will find folder "MODS" and JSGME.exe. Put those in the AC Directory. Then launch JSGME.exe and it should properly install Winter Nordschleife.