Koti Sauna is a neighborhood backyard sauna in Milwaukie, just south of Portland, named after the Finnish word for home. Its large outdoor Finnish sauna is heated to 185 to 195 degrees with three tiers of cedar benches, birch-scented steam and garden views; guests rinse in outdoor showers, sink into one of two cold plunges cooled to 40 to 50 degrees and warm up at a firepit lounge. Two-hour community sessions are booked online, private rentals start at $400, and swimsuits are required.