1. To make resistant to the harsh weather conditions of winter.

What is the meaning of weather proof?

: able to withstand exposure to weather without damage or loss of function.

What is the meaning of the term winter?

1 : the season between autumn and spring comprising in the northern hemisphere usually the months of December, January, and February or as reckoned astronomically extending from the December solstice to the March equinox. 2 : the colder half of the year. 3 : year happened many winters ago.