The climate of the U.S. Virgin Islands is tropical, hot all year round, with a relatively cooler period from December to April, with average highs around 28/29 °C (82/84 °F), and a hotter and sultry period from May to November, with highs around 31/32 °C (88/90 °F). However, the heat is always tempered by the breeze.
The U.S. Virgin Islands are an archipelago located east of Puerto Rico, in the Lesser Antilles.
Here are the average temperatures of Charlotte Amalie, the capital.
Charlotte Amalie - Average temperatures
Min (°C)222223232525262625252423
Max (°C)293030303132323232323130
Min (°F)727273737777797977777573
Max (°F)848686868890909090908886

As regards to the rainfall, there is a rainy season from May to December, with a relative decrease in precipitation in June and July. The least rainy months are February and March. The rainfall hovers around 1,000/1,200 millimeters (40/47 inches) per year and is generally slightly more abundant on the northern slopes of each island.
On the northernmost islands (Saint John and Saint Thomas, where Charlotte Amalie is located), the relatively dry season runs from December to April, even though during some years there have been heavy rains also in December, from 200 to 400 mm (8 to 16 in), while on the island of Saint Croix, located more to the south, it runs from January to April.
Starting from May, precipitation increases, though often in June and July there is a new relative decrease, followed by a recovery from August to November. Generally, the wettest period runs from September to November.
Here is the average precipitation in Charlotte Amalie.
Charlotte Amalie - Average precipitation

Apart from hurricanes, which can bring strong winds and torrential rains (see below), normally the weather is nice or variable, only interrupted by short showers and thunderstorms, which are more likely and more intense during the rainy season: so, the sun shines for many hours throughout the year, as you can see in the following table.
Charlotte Amalie - Sunshine

Charlotte Amalie

The sea in the U.S. Virgin Islands is warm enough to swim in all year round: the water temperature is around 26 °C (79 °F) from January to April, and 29 °C (84 °F) in September and October.
Charlotte Amalie - Sea temperature
Temp (°C)262626262728282829292827
Temp (°F)797979798182828284848281


From June to November, here as in the whole area of the West Indies, there is the danger of tropical storms and hurricanes, with greater probability from August to October. In September 2017, the island of Saint Croix was hit in full force by Hurricane Maria.

Best Time

The best time to visit the U.S. Virgin Islands is from December to April, since it is the least hot and outside of the hurricane period; in particular, January, February and March are the driest months. December can still be rainy, especially on the southern island of Saint Croix. In April, there is a certain increase in temperatures, and during some years also in the intensity of thunderstorms, but overall it's still an acceptable month, and in many cases it is even good. In summer, June and July are generally not as rainy as August and September, and have also a lower risk of tropical storms and hurricanes, which are most likely between August and October, when the sea is warmer and has more energy to provide.

What to pack

From December to April: pack light clothes, and possibly a scarf for the breeze and a sweatshirt for the evening.
From May to November: pack lightweight clothing, and possibly a light sweatshirt and a light raincoat for thunderstorms. A sweatshirt and a pashmina for airconditioned places.