Division of Fish and Wildlife Department of Planning and Natural Resources
Government of the Virgin Islands
CLIMATOLOGY OF THE VIRGIN ISLANDS
The Virgin Islands lie in the belt of "Easterlies" or "Trade Winds". The trade winds blow very steadily from the southeast, east, and northeast. These consistent winds make the Virgin Islands one of the finest sailing areas in the world.
The trade winds are often interrupted from December to February by "Northers", locally known as "Christmas Winds" which blow from the north or northwest. These winds are often accompanied by rain and large waves from the North.
During the spring months (March - May) the trade winds are reduced in speed and blow mainly from the east. In the summer months (June - August) the trade winds become strong again, blowing from east to southeast. July has the strongest winds of the entire year. During the fall (September - November) winds are usually their lowest, blowing from the east to southeast. The trade winds are sometimes interrupted during summer and fall by tropical storms or hurricanes that develop in the eastern tropical Atlantic and travel west to the Caribbean.
Hurricanes are tropical cyclones, or giant circular storms up to several hundred miles in diameter with wind speeds of 74 miles per hour or more. They blow in a large spiral around a relatively calm center, called the "eye". Hurricanes can generally occur in our territory between June and September. These storms usually carry a great deal of moisture. A combination of high waves and heavy rains can cause flooding in lowland and coastal areas. High winds can damage vegetation, homes and other buildings. While hurricanes can inflict severe damage on man-made structures, these natural events are important in thinning out vegetation and maintaining the diversity of plant life in our forests. Thunderstorms are localized wind storms associated with cumulus clouds (thick, dark clouds that look like domes). These clouds usually carry rain. The amount of rainfall in these islands varies, but we usually receive an average of about 41 inches a year. The more northern and mountainous areas may receive over 50 inches, while the eastern and southern lowlands may receive only about 35 inches of rain. The wettest months are September to December. The dry season is February to July, although we can often have a smaller wet period in April and May.