humid,dampness,sultry and muggy in climate topics Humid would be used to describe the amount of water in the air. Tropical climates are generally very humid. Muggy is an informal term used to describe humidity. The proper term may be "It is very humid today" but we will often say "it is muggy out today" or "it feels muggy outside today." Dampness can be used similarly "it feels damp outside today" but it is generally used for surfaces. "The carpet is damp, my clothes are damp, etc." Sultry can be used in the context of humidity but you will often only find it in literature. I would say it is more often used for it's alternative definition which is in reference to an attractive person.

The meaning of these words are basically the same: https://www.thesaurus.com/browse/sultry However, in the case of dampness, the weather can be moist and either cold or hot. I wouldn't worry too much about the differences. The weather in Florida is hot and humid (sultry, muggy). It feels muggy today. There was a dampness in the air. Winters in Uruguay are cold and damp. Sultry is not commonly used. It's basically more poetic than the other three.

Humid - “Some Islands have a humid weather”. (wet weather or air that makes people feel uncomfortable; people easily sweat) Dampness (noun) Damp (adjective) - “Today’s damp and we could barely breathe”. Something slightly wet in a way that is unpleasant “I’m not going to site on the grass; it’s still damp”. Sultry and muggy (of the weather or air)have a similar meaning: Very hot and uncomfortable. "After a nice morning, they had a sultry summer afternoon". I hope this answer helps you. Keep up the good work!