Why do you only hear the phrase “it’s not the heat, it’s the humidity,” in the summer months?

because colder air in the winter cannot hold as much water vapor, so it tends to be more humid.

because colder air in the winter cannot hold as much water vapor, so it tends to not be humid.

because colder air in the winter can hold a lot of water vapor, but it is too cold to notice it.

there is no correlation between the temperature and the humidity.