The rain is expected in Heilongjiang Province and northeastern Inner Mongolia, the China Meteorological Administration (CMA) forecast.
Moderate to strong northerly winds will blow in these areas and temperature will drop by four to six degrees Celsius, according tothe CMA.
The CMA warned of possible fires as these areas would be sunny or cloudy from May 4 to 6, with moderate winds.
Due to a lack of rainfall, a forest fire which broke out on Monday afternoon in the Hannuohe forestry center was still burning out of control on Thursday, having destroyed 15 square kilometers of forest.
The Heilongjiang provincial government has ordered artificially induced rain if conditions permit.
Meanwhile, about 200 people in Inner Mongolia succeeded in bringing another fire under control after it destroyed about a hectare of forest.