SKF has developed a range of seals with this in mind. 

Features
An oil seal and a wiper seal to minimize contamination reaching the oil seal
Specially developed NBR elastomer with lower friction characteristics
Wiper seal with optional dual lip design for high contamination situations
New oil seal lip geometry specific to fork seals

Benefits 
Increased life and performance
Enhanced water and dirt protection capability 
Reduced and constant friction over the life of seal
Much improved ride comfort
Compatibility with a wide range of OE and aftermarket oils
Reduced wear and air suction