One word for "temperature" and "humidity"

If you're looking for a more colloquial word then 'Climate' could suffice. It's not perfect but depends on the context.

Heat Index is a term that is probably what you are looking for, even though it's not a single word.

A measurement of the air temperature that factors in the effect of relative humidity, used as an indicator of the perceived temperature.

In Canada we use Humidex for precisely that.

See the article on WP for the difference with "heat index" used down south.

The humidex (short for humidity index) is an index number used by Canadian meteorologists .../... combining the effect of heat and humidity.

Although, it's been developped to describe the expected feeling that this heat and humidity will have on a person. It's not supposed to be a scientific description of the phenomenon as such, but a near-objective calculation of its effect.

Muggy

(of the weather) unpleasantly warm and humid.

• It is either Muggy or Not Muggy.
• Hot and dry is not muggy
• Cool and moist is not muggy
• Cool and dry is not muggy
• Hot and moist is muggy