My grandma used to overwinter her Boston ferns in a spare bedroom, in a 3"-tall galvanized tray about 4' x 6' that was filled with pebbles and that she kept about an inch of water in to provide some local moisture. Most ferns are pretty fussy about dry air indoors.
Outside though, wow. I remember in 2012 we had an especially rainy summer here, and these guys popped up outta nowhere next to an in-law's place and really took off. I loved them and managed to transplant a few out to a low spot in the back of my place where they'd have a better chance no matter the local rainfall levels. They didn't very much like being transplanted, as I recall, but enough of their spores settled in there over the season changes that year, so I have nice ferns out back now most years.