Monthly suicide frequencies in Switzerland are available for the period 1876-2000. Data on canton/region are available for the periods 1901-1920 & 1969-2000, & data on suicide method for the periods 1881-1920 & 1969-2000. Analyses focusing on the overall change are studied using data aggregated by quinquennia. The decrease of seasonal effects in suicide applies to a period of more than 100 years in Switzerland. Big differences of seasonal effects have existed all the time with regard to specific methods & to specific regions. The smoothing out of seasonal influences is parallel with the disappearance of the traditional rural society. (35 refs.)