Saint-Pierre sits on the leeward (west) coast of Martinique, which means it receives less rain than the Atlantic side and benefits from some shelter from trade winds. The dry season runs from December to April — this is when the weather is most reliable, the seas are calmest for diving, and visibility underwater is at its best. January to March is the sweet spot: temperatures around 26–28°C, low humidity, and clear skies.
The wet season, June to November, brings higher humidity and afternoon showers, but these are usually brief and the mornings are often clear. Diving conditions can be affected by swells and reduced visibility after rain, which is worth checking with local dive centres before booking. Hurricane season peaks in August and September; direct hits on Martinique are rare but not unheard of, and the risk is worth factoring in if you are planning around diving.
The anniversary of the 1902 eruption on 8 May draws visitors interested in the history, and a small commemoration is usually held. There is no large tourism infrastructure in Saint-Pierre, so the town never feels crowded at any time of year.