We’ve identified Seasonal Affective Disorder that occurs from the end of December through March, causing episodes of depression, increased appetite, daytime sleepiness and less energy. Researchers have determined that rates of depression and sadness among the general population of the Netherlands were highest in summer and fall due to heat.  Examples of increased aggression were identified with rising temperatures.  A study in the 1980’s determined that eight weather variables corresponded with mood outcomes.  These variables included: hours of sunshine, precipitation, temperature, wind direction, humidity, and barometric pressure. Researchers determined that high humidity caused less concentration. Sleepiness and increased pleasantness occurred in low humidity conditions. Netherlands researcher’s also identified four categories where people react to the weather. The list includes: “Summer Lovers,” “Rain Haters,” “Summer Haters,” and “Unaffected.”