People use the two words interchangeably, but they're genuinely different rooms, built around different kinds of heat.
A traditional sauna runs hot and dry — typically 150°F to 195°F, with humidity often under 20%. The heat comes from a wood, electric, or infrared stove, sometimes with water poured over hot stones (löyly, in Finnish) to send up a short burst of steam. A steam room runs cooler but soaked — usually 110°F to 120°F, at close to 100% humidity, produced by a steam generator pumping vapor into a sealed, tiled room.
That humidity difference is the whole story. Dry heat lets a sauna run much hotter than a human body could tolerate in a humid room, because sweat evaporates and cools your skin. Steam rooms feel intensely hot at a much lower thermometer reading, because the saturated air stops sweat from evaporating at all.
Steam is generally gentler on the respiratory system and skin — the moisture can help loosen congestion and is often recommended for people who find dry heat harsh on their sinuses or eyes. Traditional saunas produce a more intense sweat and are the basis of the classic hot-cold-rest cycle described on our home page, which is closely tied to Nordic and Finnish wellness traditions specifically.
Neither is inherently "better" — they're suited to different preferences and, in some cases, different medical guidance. If you have a cardiovascular condition or are pregnant, both dry saunas and steam rooms warrant a conversation with a doctor before use, since either one raises heart rate and core temperature.
Infrared saunas aren't a variant of the dry sauna — they heat your body directly with infrared light rather than heating the air around you, which is why the room itself can feel far less hot (often 120°F to 150°F) while your body still sweats heavily. That's part of why infrared studios have become popular as a separate category in their own right: the experience is more tolerable for longer sessions, even though the mechanism is completely different from a wood-fired or electric sauna.
The metro has good examples of every type. Wood-fired and traditional saunas cluster in the bathhouse category, infrared studios are their own growing scene, and a handful of spots — Watershed Spa among them — offer a true steam room alongside a sauna, so you can compare the two back to back in one visit.