Charlotte Amalie Weather: A Year-Round Climate Guide

Travel time: Year-round

Typical Weather Patterns

Charlotte Amalie, the capital of the U.S. Virgin Islands, is defined by a tropical savanna climate. This results in warm temperatures throughout the year with relatively modest seasonal variation. The environment is heavily influenced by the surrounding Caribbean Sea and Atlantic Ocean, which act as thermal buffers to prevent extreme heat or cold.

Rainfall typically occurs in short, intense bursts—often referred to by locals as "passing showers." These quick downpours are usually followed by bright sunshine, meaning that even on a "rainy" day, the sun is likely to be visible for several hours.

Daily Climate Behavior

The rhythm of the day in Charlotte Amalie is remarkably consistent:

  • Morning: The day often begins with clear skies and a gentle build-up of humidity.
  • Afternoon: This is typically the warmest part of the day, with highs reaching the mid-80s to low 90s°F (29–33°C). The steady easterly trade winds usually peak in the afternoon, providing a vital cooling effect.
  • Evening: As the sun sets, temperatures dip into the mid-70s°F (24–25°C). The air remains balmy, and the trade winds often persist, making for comfortable outdoor living.

Seasonal Trends

While there are no traditional "winters" or "summers," the climate shifts through distinct phases based on wind and rainfall.

The Dry Season (December – April)

This is often considered the most pleasant time of year. Rainfall is at its lowest, particularly in February and March. Humidity levels drop, and the sky is at its clearest. A notable phenomenon during this period is the "Christmas Winds," which are stronger-than-usual trade winds that blow from the east/northeast, often bringing choppy seas but keeping the land exceptionally cool.

The Shoulder Season (May – July)

Temperatures begin to rise, and humidity becomes more noticeable. May often sees a brief "mini-rainy season" before a drier spell in June and July. This period is also known for Saharan Dust—fine particles of sand blown across the Atlantic from Africa, which can create hazy horizons and vibrant, albeit muted, sunsets while temporarily suppressing rainfall.

The Wet Season & Hurricane Season (August – November)

This is the hottest and most humid time of year. Daytime highs frequently hit their annual peak. September and October are statistically the wettest months, and the threat of tropical cyclones is highest. While many days remain sunny, this window carries the risk of organized storms that can bring heavy rain and high winds.

Microclimates and Variations

St. Thomas is a rugged, volcanic island, and its topography creates distinct microclimates:

  • The Windward (North) Side: Areas like Magens Bay often receive slightly more rainfall and are greener due to moisture-laden air rising over the island's central ridge.
  • The Leeward (South) Side: Charlotte Amalie's harbor is nestled on the southern side. Because it is shielded by the central mountains, it can feel several degrees warmer and significantly more humid than the exposed northern slopes, as the hills block some of the refreshing trade winds.
  • Elevation: Higher points on the island, such as Crown Mountain (1,555 ft), can be 5–10°F cooler than the harbor at sea level.

Historical Context and Phenomena

Historically, the U.S. Virgin Islands have been shaped by significant hurricanes, most notably Hurricane Hugo (1989) and the twin impacts of Irma and Maria (2017). These events have dictated local building codes, with most structures featuring heavy-duty shutters and cisterns to collect the frequent tropical rainwater.

A unique local phenomenon is the "Groundswell." During the winter months, large northern swells generated by distant storms in the North Atlantic can reach the islands. While the weather in Charlotte Amalie may be perfectly sunny, these swells can cause massive waves on the north shore, even while the south harbor remains calm.

The Local Experience

Locals have a deep respect for the "power of the sun" and the "refreshment of the rain." You will often see residents adapting to the heat by moving slower during the peak afternoon hours and utilizing natural ventilation in traditional West Indian architecture. Rain is rarely seen as a negative; it is the lifeblood of the islands, as most homes rely on cisterns to collect and store rainwater for daily use.

Perceptual Conditions (The "Feel")

Because of the high humidity (often averaging 70-75%), the "RealFeel" or heat index is almost always higher than the actual thermometer reading. In the summer, an 88°F day can easily feel like 98°F. However, the trade winds are the great equalizer—without them, the tropical heat would be oppressive. In the winter, the lower humidity and consistent breezes create a "crisp" tropical feel that is considered the island's most comfortable weather.