Research on well-being is in its infancy and the term lacks a clear definition, yet it is an increasingly popular matter. The neurology underlying well-being is important in such research in order to understand what brain mechanisms are correlated with mental health. Even though objective measures such as brain imaging are increasingly used assessments in well-being and neuroscience studies, self-reports are widely used. Articles viewing such research often state that self-reports could be biased because the subjects may be affected by the weather the day of the self-report. No further explanations are however provided as to why or how those individuals would be affected by the weather, or by which weather conditions. The aim of this thesis is thus to find neurological explanations for how weather can affect well-being. Constituents of well-being will be reviewed together with brain bases of mental health in an attempt to find neural correlations of weather and well-being. How humans are affected by the weather is a limited research area and the findings are diverse on all aspects but the solar influence over the brain and mind. Man-made light was however found to be a substitute for the effect of sunlight on the brain. No strong relationship between weather and well-being were found based on existing literature. No significant neural correlations between mental well-being and different weather conditions was found either.