1. A strong suggestion of storm effect is seen in the distribution of suicides and homicides in North American cities. The rates are not highest where industrialization is most advanced, but rather where barometric pressure and temperature changes are most frequent and severe.2. Suicides show a definite time relationship to weather changes as high- and low-pressure centers approach and pass by. With tailing pressure and rising temperature, suicides rapidly rise. Most peaks in frequency occur at the time of a low-pressure crisis. With rising pressure and falling temperature few suicides occur.3. Migration from the South into the more stormy North is accompanied by a marked rise in suicides among negroes. Figures are not available to show whether the same is true of the whites. Increased economic stress in the North may, of course, play a large part in this rise.4. These findings indicate the likelihood that the wide shifts in temperature and pressure that accompany North American storms may play a considerable part in producing the mental instability of our population and the rising rate of breakdown. Much of this storm effect probably works through increasing the tempo of life and the economic competition. There probably remains, however, a distinct disturbing action of the storm changes as they affect the body directly.