This alters the weathers of Vvardenfell to add the Blight weather type to nearly every region of the island. This is mainly to show that the Blight is an expanding threat that goes beyond the Ghostgate. The only region that's untouched is the Ascadian Isles (unless you have the optional addon), mainly because it makes sense that Vivec would want to keep the Blight out of the general vicinity of his city. The altered percentages are as follows: 

The Ashlands: 25%
Sheogorad: 5%
Azura's Coast: 3%
Bitter Coast: 5%
Molag Amur: 20%
Grazelands: 15%
West Gash: 10%
-
Ascadian Isles Addon: 10%

The percentages were largely determined by both distance from Red Mountain and natural barriers that would prevent the Blight from being carried there. For example, the Grazelands and West Gash regions have different percentages despite being relatively the same distance from Red Mountain. The reason behind this is the geography in both regions, with the open air Grazelands having fewer obstacles to get in the way of the Blight than the rockier, uneven terrain of the West Gash.

NOTE: Do not install after killing Dagoth Ur. This will cause Blight to reappear in the game.

Conflicts: Will be incompatible with mods that alter the weather percentages of the game. Scripted weather changes are quite likely to be compatible, though.