Gustavia, the capital of Saint Barthélemy, experiences a tropical maritime climate defined by remarkably stable temperatures and two distinct seasons. With approximately 3,000 hours of sunshine annually, the weather is almost always conducive to outdoor life, though the "feel" of the air shifts significantly between the dry and humid periods.
Seasonal Rhythms
Locals divide the year into two primary seasons based on rainfall and wind patterns rather than temperature fluctuations:
- Le Carême (The Lent): Running from December to May, this is the dry season. It is characterized by lower humidity, clear blue skies, and the cooling influence of the steady Alizés (trade winds). February and March are typically the driest months, with rainfall dropping to its annual minimum.
- L’Hivernage (The Wintering): Despite the name, this period from June to November is the hottest and most humid time of year. While mornings often start sunny, tropical showers or thunderstorms are common in the late afternoon. This season also coincides with the Atlantic hurricane season, with the highest activity historically occurring between August and October.
Daily Weather Behavior
A typical day in Gustavia is governed by the sun and the sea. Mornings usually begin clear and bright. As the day progresses, the tropical sun heats the land, occasionally triggering brief, intense "liquid sunshine"—passing rain showers that often vanish within minutes, followed immediately by sun.
Evenings bring a welcome drop in temperature, though the mercury rarely dips below 72°F (22°C). In the harbor of Gustavia, the high stone walls and surrounding hills can sometimes trap heat during the day, making the town center feel a few degrees warmer than the exposed beaches.
Temperature and Humidity
Temperatures in Gustavia are remarkably consistent. Tropical heat is the norm, with daytime highs ranging from 82°F (28°C) in the winter to 89°F (32°C) in the height of summer.
What truly differentiates the seasons is the heat index. During Le Carême, the low humidity and constant breeze make the heat feel crisp and pleasant. During L’Hivernage, the rising humidity can make the air feel "heavy" or oppressive, particularly on days when the trade winds stall.
Microclimates and Variations
Despite its small size (eight square miles), St. Barts exhibits subtle microclimates.
- Windward vs. Leeward: The eastern (windward) side of the island receives more direct wind and slightly more frequent showers. Gustavia, located on the western (leeward) side, is more sheltered and tends to be drier and calmer, especially within its horse-shoe-shaped harbor.
- Terrain Influence: The island's hilly interior can cause localized rain. It is a common phenomenon for it to be pouring rain in the hills of Lorient or Colombier while the sun remains bright over the docks of Gustavia.
Tropical Phenomena
- The Alizés (Trade Winds): These northeast winds are the island's natural air conditioning. They are most consistent from December to April. Their absence during the summer months is a signal to locals that a more significant weather system may be approaching.
- Hurricanes: St. Barts lies in the path of Atlantic cyclones. While direct hits like Hurricane Irma in 2017 are rare, the island is highly adapted to these events. Local architecture often features heavy-duty shutters and reinforced concrete to withstand extreme wind speeds.
- Sargassum Seaweed: While not a weather event per se, certain wind and current patterns (often in late spring and summer) can bring influxes of sargassum to the windward beaches, though Gustavia's western location generally keeps its immediate shores clear.
Local Perspective
Residents of Gustavia monitor the "state of the sea" as much as the sky. The winter months often bring the "Christmas Winds," which can create a "ground swell"—heavy surf that rolls into the harbor even when the local weather is calm. Locals have a deep respect for the sun; you will often see the town's pace slow down between noon and 3:00 PM, when the solar elevation is at its peak and the heat is most intense.