Low atmospheric humidity stresses the skin and that is why we use creams to protect it against dehydration. Though, conditions are quite different in rainy weather with high relative humidity. The transepidermal water loss then decreases considerably which naturally leads to an ideally hydrated skin. There is no need for an external skin care that sometimes even can have counterproductive effects.
Rainwater can even be defined as the prototype of soft water and is practically free from salts. Entirely different though is the hard water from the tap. It contains calcium and magnesium salts which not only leave their traces in taps and kettles but also can damage the skin barrier. Originating from evaporation and condensation, rainwater is very similar to distilled water. Hence a proven remedy for beautiful skin is to expose it to rainwater, where besides hydrating effects also temperature effects have a positive impact. An increased microcirculation and skin tightening as well as the filtered clean air come as an additional bonus pack. Well, maybe this is one of the reasons why man and women tend to come closer on rainy days?
Dr. Hans Lautenschläger