In eight long‐term examination series it could be shown that the efficiency of healing processes during summer months is favoured significantly by the increase in the number of bright days in the curing period. Three other series of observations give evidence of the fact that meteoropatholo‐gical disturbances augment with the increase of clouded, dark days in summer and less cloudy, bright days in winter. Variations of the diurnal rhythm imply that from winter to summer the ergo‐tropic phase in the course of human regulation anticipates by 1 to 2 hrs and ends with a delay of about 1 hr in the evening. These phase shifts are superposed by shifts of 3 or 4 hrs with a rhythm of about 35 days.