ABSTRACT
The study of the relationship between weather and health is called biometeorology. The body has natural rhythms that get entrained to the external cycle of light and dark, called circadian rhythms. The rhythms are governed by the absence of and exposure to bright light falling on the eye. Animals, including humans, evolved to sleep when it's dark, and artificial light is a very recent evolutionary event. There is much evidence that night-time light is a very bad thing, leading to sleep disruption and mood disorders, reducing our ability to concentrate, interfering with hormone function and food metabolism, weakening the immune system, increasing the stress response, and increasing the chance of some cancers, particularly breast cancer. Germany sometimes advertises a medication's ability to treat Fohn krankheit or Fohn sickness. Fohn winds roll down mountainsides, warming the weather by up to 28°C in a matter of hours, and they're largely responsible for Central Europe's relatively mild temperatures.
