Dénia has a Mediterranean climate (Köppen classification Csa), characterized by mild winters and hot summers. The average annual temperature exceeds 18 °C. The coldest month, January, has an average temperature of about 12 °C, while the hottest month, August, averages around 26 °C.

The annual rainfall is around 750 millimeters per square meter. Autumn is by far the wettest season, receiving over 300 millimeters of rainfall, mostly concentrated in a few days with intense downpours due to a weather phenomenon known in Spain as Gota Fría (“cold drop”), which is common along the Valencian coast. September and October each record over 100 millimeters of rain, while November approaches 100 mm. Summer is the driest season, though not completely dry. On average, it receives about 70 to 80 millimeters of rain, with July being almost rainless, averaging under 5 millimeters and standing out as the sunniest month.

Storms are most frequent in autumn, with about 15 stormy days per year, while sunshine is abundant year-round, with an impressive 322 sunny days annually. Dénia enjoys a mild and sunny climate, receiving approximately 2900 to 3000 sunshine hours per year, which is a high figure by European standards, comparable to the Caribbean (2800–3100 hours) and significantly more than southeastern Norway (1850 hours), the Netherlands (1600 hours), or southern England (1481 hours).