The Polish city of Gdańsk, of the then Polish-Lithuanian Commonwealth. He was also born there at the time. [1]

> He defined 0 degrees as the coldest measurement, 100 the hottest measurement.

Nope. It was neither about the temperatures in Gdańsk, nor about the temperature of his wife, btw. ;) [2]

  [1] https://en.wikipedia.org/wiki/Daniel_Gabriel_Fahrenheit
  [2] https://en.wikipedia.org/wiki/Fahrenheit