Douglas Harper's Etymology Dictionary
1946, from weather (n.) + -ize. Related: Weatherized; weatherizing.
Wiktionary
alt. (context US English) To protect a structure against damage by the weather. vb. (context US English) To protect a structure against damage by the weather.
Usage examples of "weatherize".
Sherkaner’s place was up there somewhere, among those rich enough to weatherize the high ground of an estate, but too cheap to rebuild down at the bottom.
The utility did continue to support our extensive efforts to weatherize the homes of low-income people, which made them cooler in the summer and warmer in the winter, and cut their utility bills considerably.
Instead, a long, open pavilion with chairs sat not far from the control area, with a large flatscreen monitor installed in its own weatherized enclosure to one side to provide alerts and alternative views of the landing.