During the summer of 2013, 70 people received Diarrhetic Shellfish Poisoning following consumption of mussels harvested in the Shetland Islands, Scotland. At this time, large numbers of the biotoxin-producing phytoplankton genus Dinophysis was observed around the Shetland Islands. Analysis indicated this increase was not due to in situ growth but coincided with a change in the prevalent wind direction. A previous large bloom of Dinophysis during 2006 also coincided with a similar change in the prevalent wind patterns. Wind direction and speed in the North East Atlantic and the North Sea is strongly influenced by the North Atlantic oscillation (NAO) with a positive relationship between it and wind direction. It has been noted that a positive trend in the NAO is linked to climate change and predictions suggest there will be an increasingly westward component to prevalent wind directions in the North Sea which could lead to an increase in the occurrence of these harmful algal blooms. Analysis of wind patterns therefore offers a potential method of early warning of future bio-toxicity events.