sultriest
/ˈsʌltriɪst/Definitions
1. adjective
having or characterized by the quality of sultriness; hot and humid
“The sultriest summer days made it difficult for people to stay outdoors for long periods.”
2. superlative form of sultry
most sultry; hottest and most humid
“This summer was the sultriest on record, with temperatures soaring to record highs.”