Time-series analysis was used to study the associations between daily weather variables and symptomatology in a man suffering from recurrent anxiety. Outcome measures were the patient's main symptoms: anxiety and energy. Wind direction appeared to be related to the patient's energy levels; these were significantly lower when the wind blew from the southeast. This effect could not be explained by other weather parameters. Decreases in energy in turn predicted increases in anxiety. The reverse effect was observed as well, with increases in anxiety predicting decreases in energy, indicating a positive feedback loop.