Muggy is a synonym of misty.
As an adjective muggy
is humid, or hot and humid.
As a proper noun misty is
from the adjective "misty", reasonably popular in the 1970s and the 1980s.
humid, or hot and humid.
* (of the weather) , oppressive, sultry
With mist; foggy.
(figuratively) With tears in the eyes.
- It’s a very misty morning this morning - I can’t see a thing!
- ''Her eyes grew misty the night her long-time friend passed away.