From Longman Dictionary of Contemporary Englishmuggymug‧gy /ˈmʌɡi/ adjective informalWET muggy weather is unpleasantly warm and the air seems wet SYN humid► see thesaurus at damp, hot, wet
Examples from the Corpus
muggy• It was warm again, warm and muggy.• It was a warm muggy afternoon, and it looked like it would rain.• The air now had a muggy, almost tropical, feel.• The coast was rough country and the big rucksack a burden in the muggy atmosphere.• But on this muggy August afternoon, with no open windows, its failure is guaranteed.• It is another hot muggy day.• It was a hot, very muggy evening.• Summer is hot and muggy in the Deep South.• When it's hot and muggy, no one feels like working.• I meet her, in my unflattering dress, at the Warrior one muggy Saturday.• The prestigious venue was host to 46 teams on a muggy Sunday.Origin muggy (1700-1800) mug “light rain” ((1700-1800)), probably from a Scandinavian language