WATER ENTRY THROUGH CAPILLARY ACTION
If your tights aren't water repellent, they're highly likely to soak up rain. Even the best overshoes in the world wouldn't help: if your tights are in contact with your socks, they'll absorb water through the capillary effect.
This is why VAN RYSEL only creates winter tights with a water-repellent membrane, such as the RACER long tights.