A Met office bulletin said the state capital Patna recorded a maximum temperature of 41.4 deg C, while Bhagalpur's maximum settled at 41.8 deg C and Purnea at 37 deg C.
In its forecast, the Met office said south west and south central parts of Bihar may witness maximum temperatures above 40 degrees Celsius tomorrow.
It has also forecast partly cloudy skies with possibility of thunder or rain in some parts of Bihar.