Despite their lashing winds and rains, strong typhoons in the western Pacific Ocean also help to cause the dry season in Southeast Asia.

Typhoons regularly unleash punishing rains on the Maritime Continent, the expanse of islands and sea that lies between the Indian and Pacific oceans and that includes the Philippines and Indonesia. Using more than 35 years of historical weather data, Enrico Scoccimarro at the Euro-Mediterranean Centre on Climate Change in Bologna, Italy, and his colleagues compared monthly measures of the strength of typhoons in the tropical western Pacific with precipitation over the Maritime Continent and the nearby ocean.

Compared with weak typhoons, stronger storms brought heavier precipitation over the ocean, but were associated with drier months in the Maritime Continent. This relationship held even after the team controlled for large-scale climate phenomena, such as El Niño.

The researchers’ computer simulations suggest that typhoons and dryness are linked because the storms carry atmospheric water vapour eastward, away from the landmasses. Improving typhoon forecasts, the authors say, could help to better predict the onset of Southeast Asia’s dry season.