The Columbian exchange is the name given to the enormous transfer of plants, animals, culture, humans, technology, diseases and ideas that followed the arrival of Europeans to the Americas in the 15th century. This exchange altered the lifestyle and culture of people all over the world. In this map, we see a list of products that originated in America and were transferred to Europe, Africa and Asia on the left side, while the other side describes products that travelled the other way.
August would be the best guess. The warmer waters allow for the hurricanes to build up speed and momentum, causing for more tropical storms to be upgraded