PURPOSE: To realize a timer device equipped with the rainfall probability judgement function which can display the tendency of the more correct weather and the result of the judgement of the rainfall probability.

CONSTITUTION: A timer device is equipped with a device clock 11 which measures and displays time, atmospheric pressure measuring part 10 for measuring the atmospheric pressure, RAM 27 for recording and renewing the atmospheric pressure data measured in the atmospheric pressure measuring part 10 at each certain time, ROM 28 as the data base in which the rainfall probability data for the time change of a variety of atmospheric pressure is accommodated, signal processing part 26 which compares the atmospheric pressure measurement data in the time sequence of the RAM 27 and the atmospheric pressure data of the ROM 28 and judges the rainfall probability by extracting the data having the state in the time change of the atmospheric pressure and in a matched state, and a judgement result display device for displaying the result of the judgement of the signal processing part 26. The ROM 28 as data base consists of the data in each used region, week, or season, which is selectively used.