Gear guide · June 2026
Short answer: no. Also no to the AirPods, and no to the Apple Watch. A traditional sauna runs around 80°C (176°F), which is a temperature your consumer electronics were emphatically not designed to sit in, and the companies that make them will tell you this themselves if you read the fine print (nobody reads the fine print). So here is the fine print, device by device, with links. Then the genuinely good news, which is that you don't need any of this gear in the heat to find out whether the sauna is working.
The basic problem
The whole thing comes down to two numbers that do not get along. Most consumer electronics, iPhone and Apple Watch included, are rated for air up to about 35°C (95°F). A traditional Finnish-style sauna sits around 80°C (176°F), hotter on the top bench. That is not a rounding error you can sneak past; it's more than double the ceiling the device was built for. For reference, the big Finnish longevity studies clocked their saunas at an average of 76–79°C, which is to say a real sauna and a survivable phone are simply not operating in the same thermal universe (more on those studies here).
Device by device
Leave it outside
Built for 0–35°C (32–95°F) air
A sauna is more than twice as hot as the top of that range. Apple also notes, in the dry way Apple notes things, that heat can permanently shorten battery life. Not just for the session. Permanently.
Source: Apple's temperature guidelines
Leave it outside
Built for 0–35°C (32–95°F) air
Same ceiling as the iPhone. And there's a punchline: when the Watch overheats it defends itself by shutting down to a red thermometer icon and the time, which means the heart-rate data you went in to collect simply stops collecting. You'd be cooking the device for nothing.
Leave them outside
Apple's words: don't
This one needs no interpretation. Apple writes, in a complete sentence, “Don't wear AirPods in a sauna or steam room.” The sweat-and-water resistance is for workouts and rain, not heat, and it fades over time anyway.
Source: Apple's AirPods care page
Infrared maybe, a hot sauna no
Whoop's line: fine below 60°C (140°F)
Whoop will tell you the band is fine in a sauna as long as the room stays below 60°C (140°F), and then leaves you to do the arithmetic. The arithmetic: most infrared cabins squeak under that line, and a traditional sauna at 80°C sails right past it. Their actual advice is to watch the temperature, which is a polite way of saying hot rounds, band off.
Source: Whoop's official guidance
Allowed on paper, over the line in a real sauna
Rated to 52°C (125°F), damage risk above 60°C (140°F)
This is the interesting one, because Oura's safety page cheerfully lists saunas as fine, and the same page rates the ring to 52°C and warns that extended time above 60°C can damage the battery. A traditional sauna runs around 80°C. Both of those things are printed by the same company, on the same page, and only one of them survives contact with an actual Finnish sauna. An infrared cabin is within range; the hot stuff is not, which is why a lot of owners just slip the ring off for the hot rounds.
Source: Oura's product safety page
Ratings are taken from each maker's official support pages as of June 2026 — follow the links and check the current pages before trusting any blog, including this one.
The good news
Here is the part that makes the whole worry kind of moot. Even if your watch could shrug off 80°C, the numbers it took in there would barely be worth having. In serious heat everyone's heart rate goes up; that's the heat doing its job, not a personal readout, so a big number in the cabin mostly confirms that the cabin is, yes, a cabin. The readings that actually say something about whether the practice is doing anything for you all happen later, outside the hot room: your resting heart rate the next morning, how you slept, where your recovery drifts across weeks of regular sessions.
And your wearable already records every bit of that overnight, at room temperature, doing exactly what it was designed to do. So the setup that works is almost insultingly simple: keep the gear out of the heat and read the story afterward. That's the entire premise of Sauna Score, which compares your weeks of regular sauna use against your quieter weeks using the sleep, heart-rate, and recovery data your devices already write to Apple Health, with nothing ever going into the heat. The session timer assumes the same thing: lock the phone away at a gym and log the sit afterward, or in your own sauna leave it just outside the door, where its time-sensitive alarm is loud enough to reach you through a locked screen.
If you're shopping for an app to do this, there's a rundown of the best sauna apps of 2026, including the ones that are, in fact, built around wearing a watch into the heat, in case that is the hill you want to cook your watch on.
FAQ
Officially, no. Apple builds the iPhone for air temperatures up to 35°C (95°F), and a traditional sauna runs around 80°C — more than double the ceiling. Short of that, the phone will throttle itself, may shut down with a temperature warning, and Apple cautions that heat can permanently shorten battery life. The safer move is to lock it away and log the session afterward, or, in your own sauna, leave it just outside the door with a timer loud enough to reach you.
It defends itself. iPhones slow down, dim, switch off features like the flash, and eventually display a temperature warning and shut off until they cool. The part you don't see is the part that matters: Apple says heat exposure can permanently reduce the battery's capacity, so the damage can outlast the session.
Apple's guidance is one sentence: “Don't wear AirPods in a sauna or steam room.” Their sweat-and-water resistance is designed for workouts and rain, not for heat, and it degrades over time. If you want sound in the sauna, a speaker outside the hot room is the safe version.
It's rated for the same 0–35°C air as the iPhone, so a sauna is far outside spec. And there's a second catch: when an Apple Watch overheats it shuts down into a red-thermometer screen — meaning the heart-rate data you wore it in for stops being recorded anyway. You risk the hardware and still don't get the numbers.
Whoop's official answer: yes, as long as the room stays below 60°C (140°F). That makes it an infrared-cabin yes and a traditional-sauna no — Finnish-style saunas run around 80°C, well past Whoop's stated ceiling. If you sauna hot, take the band off for the rounds and let it catch the recovery story overnight instead.
Oura officially allows it — their safety page lists saunas as fine. But the fine print on the same page rates the ring to 52°C with battery-damage risk above 60°C, and a traditional Finnish sauna runs around 80°C or hotter. An infrared cabin at 45–60°C is inside the range; a hot sauna is not. If you love the ring, the cautious move is to slip it off for the hot rounds.
By reading the data around the session instead of during it. Your wearable already measures your morning baseline before the sauna and your sleep, heart rate, and recovery overnight after it — from the safety of your nightstand or wrist at normal temperature. That before-and-after trend over weeks is where the meaningful signal lives anyway; that's the comparison Sauna Score runs on your Apple Health data.
Sauna Score times your session from outside the hot room and reads your body's response from the data your devices already collect, overnight, at room temperature, where they belong.