I have serious doubts about your statement " I know papaya prefer 180 inches a year ...
".
We live in an area classified as a 150 to 160 inches a year of rainfall, also rated as USDA 12a-12b.
Our local rainfall is probably even higher.
We're on the windward side of the island at 750' at the top of a pali where the clouds make a quick steep rise.
Papayas are grown locally commercially in large orchard settings, but at lower elevations, closer to sea level where it is warmer and drier.
I see pickups with their beds filled with yellow spotted green papayas driving to the markets and other places around the island.
Temperature may be a factor, but most likely because our area is too wet for them.
Wet climate also means less sun because of cloud cover.
Nobody grows papaya in our area.
When they try, they give up.
I've seen 10' and up trees ripped out of yards around here because they were a waste of time and space.
Everybody tries to grow some type of tropical fruit in their yard around here.
I've got various bananas, various tangerines, oranges, limes, ledmons, longans, mulberry, pineapples - yellow and white, various avos, and jaboticabas. There might be more that don't come to mind right now, but no papayas anymore.