Fonds-Saint-Denis has a tropical rainforest climate (Köppen climate classificationAf). The average annual temperature in Fonds-Saint-Denis is 23.7 °C (74.7 °F). The average annual rainfall is 2,944.9 mm (115.94 in) with July as the wettest month. The temperatures are highest on average in September, at around 25.0 °C (77.0 °F), and lowest in February, at around 22.0 °C (71.6 °F). The highest temperature ever recorded in Fonds-Saint-Denis was 33.4 °C (92.1 °F) on 9 March 2010; the coldest temperature ever recorded was 14.4 °C (57.9 °F) on 12 February 1966.
Climate data for Fonds-Saint-Denis (1991–2020 averages, extremes 1915−present)