What measure do Haitians use for temperature? Fahrenheit or Celsius? How would I say this in creole according to their measurement. "In Haiti it is usually 80 or 90 degrees, but here it is only around 35 degrees."

They use both.
Celsius → degre sèlsiyis or degre santigrad
Fahrenheit → degre farennayt

In Haiti it is usually 85 or 90 degree F, but here it is only 35 degrees.

Dabitid, an Ayiti li fè 85 oubyen 90 degre Farennayt, men isit la li fè sèlman 35 degre.

In Haiti it is usually 29 or 32 degree Celsius, but here it is only 2 degrees.
Dabitid, an Ayiti li fè 29 oubyen 32 degre santigrad, men isit la li fè sèlman 2 degre santigrad.
Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words