While fiber optics are tough, cold temps can cause trouble. Water in cables can freeze, potentially harming connections. Waterproofing prevents icy issues. We break down exactly why this happens, what will fail first, and how to fix it yourself or force your ISP to do it right. There is, however, a challenge to be overcome: the delicate nature of the optical fiber means installation and maintenance must be carefully managed. Tiny amounts of grease, dirt or. Cold weather can affect fiber optic cables, but they are generally more resilient to temperature extremes compared to other types of cables, such as copper.