In the temperate regions of the world rain normally forms as ice and snow crystals in the upper atmosphere. It melts as it falls to earth, but can still be cooler than the air it falls into. The high heat capacity of this cool rain can have a noticeable chilling effect on the air at ground level. It can also quickly chill the outer fabric of your clothing system to below the dew point, causing condensation.
FurTech clothing keeps condensation, caused by chilling of the outer fabric, away from the body and allows it to drain away or dry as conditions improve.