When you connect a coaxial cable to an outdoor antenna, even though the connection may seem tight, the metal-on-metal threading connection won't be 100% waterproof. Heavy rains and humidity can lead to corrosion inside the connection area over time which can shorten the life of your outdoor setup.
Rokland recommends using a waterproof silicon-based tape to seal off the connection area where your coaxial cable connector connects to your antenna.
A properly sealed connector area will completely weatherproof your outdoor antenna setup. Tape like ours withstands heat and elements, but it may be a good idea to replace your tape over time.