暑い vs 熱い — the trick is asking 'can I touch it?'

Simple rule that finally made this stick for me: 暑い is exclusively for AMBIENT temperature you can't touch — weather, a room, a season (今日は暑いね, 夏は暑い). 熱い is for something with a specific, touchable temperature — a cup of coffee, a bath, a stove, or even figuratively 'passionate' (熱い議論 = a heated/passionate debate). If you can point at a physical object and say 'that thing is hot,' it's 熱い. If you're describing the air around you, it's 暑い. Neither is 'more correct' — they're just non-overlapping domains.