Can I still go to the sauna as a Muslim?

The issue isn't the heat

Islam has no problem with saunas, steam rooms or hot baths. The hammam, a public steam bath, was part of daily life in many Muslim cities for centuries. Relaxing your muscles after the gym is perfectly halal.

The issue is covering and looking

The Prophet Muhammad ﷺ also said: "A man should not see the private parts of another man, and a woman should not see the private parts of another woman" (Sahih Muslim 338).

So even in a single-gender sauna, nudity in front of others isn't allowed. For men, the awrah is at least from the navel to the knees. For women among women, scholars say the same area must stay covered at minimum. See Can I still get a massage as a Muslim?

European sauna culture

In Germany, Austria, the Netherlands and Scandinavia, many saunas are "textile-free" (nude) and often mixed. That kind of sauna isn't permissible for a Muslim to attend. Look instead for:

• Women-only or men-only days, which many spas offer.
• Gym saunas in single-gender changing areas, where towels are allowed.
• Private sauna cabins you can book for yourself or your family.
• Turkish or Moroccan hammams, usually separated by gender.

A note for women

Even in women-only areas, keep from the navel to the knees covered and use your judgment about others' phones and cameras. A private cabin or home sauna avoids most concerns.

For a similar question, see Can I still go swimming at a public pool as a Muslim?

Prayer and saunas

Sweating doesn't break your wudu, so you can pray afterward without repeating it, unless something else has broken it. Just make sure your clothes are clean.