Sleep can be most restful for older adults when nighttime temperature range is between 68 to 77°F, study finds

20-25°C

That seems a bit warm for me, I'm wondering whether the study was done using people in a hot region and therefore acclimatised to higher temperatures. I haven't found the full text of the article to confirm my guess but it does seem likely since it's talking about finding decreases in sleep quality when bedroom temperatures rise from 25° to 30°.

That sounds horrific. 20+ degrees. Pretty sure we sleep in rooms that are 4c.
I'm going to put a thermometer in tonight and check to see how cold it gets. No chance I'd be having a restful sleep at temps above 20c. I'd be cooking with covers of naked

I’m 45 and can’t sleep in anything above 20°C

Summer is terrible for my sleep schedule.

The temperature I prefer to sleep at is 15°C. My bedroom window stay opened all days of the year and I don’t heat.

20 to 25°C in superior units

I am not at peace when I am asleep unless I am in a room that is as cold as an ice maker

My setback thermostat goes to 16C (61C) at 11:00pm. Winter is when I sleep the best.
In the summer, I just go to 21 with the AC.

Anything above 72°F and I get headaches when I wake up, just the most uncomfortable sleep.

Good thing I only sleep in Celsius

My initiative reaction is that this sounds stupidly obvious. You sleep better at temps you find comfortable.