Wind-gear is often only partially or semi water REPELLENT. Depending upon the fabric used and how its treated to resist water penetration, wind-gear may only provide 10-20 minutes typically of water resistance in light to moderate rain. Some HIGHLY water resistent wind gear, Epic finished/treated fabrics may survive several hours of moderate to heavy rain, but will eventually wet out/through. Raingear, on the other hand, is generally WATERPROOF (vs. merely resistant), but, typically, at the expense of breathability. So, in high activity endeavors, one can expect to get wet from the INSIDE, i.e. fr/one's own sweat - though this is true of windgear also, but perhaps to a lesser extent in some cases.
Also, windgear is generally much lighter weight than raingear and the fabrics softer to the touch due to lack of a WPB (water-proof breathable) membrane.
There is also WP (water-proof) materials like that used in most ponchos and capes that doesn't "breathe" at all.
The above represents a summation of the characteristics of the wind & rain gear, generally/cateogorically speaking, that i'm familiar with.