There’s no need to bring poly inside no matter what the season—it can be left outside all year. Poly will hold its color for decades with very little fading.
Unlike wood, poly won’t rot, split, or crack, and is impervious to insect damage. Plus, because the color runs throughout the lumber, small nicks and scratches never need to be touched up.
Finally, poly furniture is easy to keep clean. Occasional washing with mild dish detergent and rinsing are all that’s needed to keep it looking like new.