That also depends on the airline. Japanese airlines seem to be more on the hot side, LH probably in the middle, American airlines more on the cold side.

It also depends on where you sit on the plane. Seats near the exits tend to be colder, and window seats are probably slightly colder.

And it will also depend on who complains how strongly to the FAs demanding an adjustment of temperature. As people have a different perception of hot/cold, and that perception shifts over the course of a year (20 degC inside is warm in the winter, in the summer 20 degC inside will appear cool (this may not apply for people strongly relying on airconditioning to have 27 degC in the winter and 15 degC in the summer)), there will always be people on board complaining that it is too hot and others complaining that it is too cold.

Best to wear layered clothes and bring something along in addition.

HTB.