According to an example, build temperature modulation may include determining a characteristic of an object to be produced by three-dimensional printing. The three-dimensional printing may divide the object into a plurality of printing areas for producing the object by using a fusing agent. The build temperature modulation may further include determining, based on the characteristic of the object to be produced by the three-dimensional printing, a fusing agent flux amount of the fusing agent sufficient to oversaturate a printing area of the plurality of printing areas to modulate temperatures related to the plurality of printing areas to a substantially constant temperature across the plurality of printing areas.