Why the weather influences our psychology

• One possibility is that the effects of weather on mood are mostly physiological. Heat causes discomfort by taxing our bodies to regulate temperature, leading to irritability and aggression.
• Sunlight produces vitamin D and promotes the production of serotonin - which is a mood lifter.

However, the weather will only influence us if we expose ourselves to it. In industrialised societies, people only spend 7% of their time outside.