Climate in Macao
Located along the southeast coast of Mainland China, Macao is bordered on Zhuhai City of Guangdong Province to the north, facing the Hengqin Island in Zhuhai to the west and Hong Kong across the Pearl River Estuary to the east. Surrounded by the sea on three sides, it is exposed to direct solar radiation twice a year with a subtropical oceanic monsoon climate that is characterized by intense radiation, exuberant evaporation, rich heat, adequate moisture, high temperature, and abundant rainfall.
Bordering the Asian continent in the north and the tropical ocean (the South China Sea) in the south, Macao is influenced by the mid- and high-latitude atmospheric circulation from the continent and the low-latitude atmospheric circulation from the ocean. For this reason, Macao lies in a typical monsoon climate zone because of the obvious circulation conversion between winter and summer.
In winter, the upper air in the Asian continent is dominated by the west wind drift current. In the southern Asia, there is a westerly jet stream, which is divided into the south and north branches around the Tibetan Plateau. The South China and the northern part of South China Sea sit in the south of the southern branch jet, where the subtropical westerly is prevailing. The upper air in Macao is also controlled by the subtropical westerly. As a result, the western pacific subtropical high is weak and stays in the south. The ground of the Asian continent is controlled by a strong cold high. Located on the southern edge of the cold high, Macao is often influenced by the airflow from north to northeast. Due to the repeated outbreak of the cold current southward, the strong cold northerly airflow can directly reach Macao, bringing about cold and dry weather. Therefore, Macao often experiences the north monsoon in winter as well as a dry and cold climate.
In summer, the north and south westerly jets in the upper air merge and move northwards to the north of 40°N. A strong anticyclone builds up in the upper air of the Tibetan Plateau, where the tropical easterly jet is prevailing in the south. The upper air in the South China is controlled by the easterly airflow. As a result, the subtropical high is significantly strengthened westwards and controls the southern part of China. Therefore, the northeast monsoon is replaced by the strong southwest monsoon, and the southern part of China often experiences southerly airflow along the coast. Due to the influence of southerly airflow and summer monsoon, Macao gradually transits from the first rainy season with heavy rains to the second rainy season with more typhoons and heavy rains, often having hot and rainy weather during the period.
For spring and autumn, their seasonal interchange period is short. In spring, Macao stays in the interchange period from the winter monsoon to the summer monsoon. Cold and warm airflows converge frequently, and the quasi-stationary front in the South China is active. Consequently, Macao often experiences cold and rainy weather. In autumn, under the effect of cold air, the summer monsoon in the South China is gradually replaced by the northerly winter monsoon, accompanied by less rainfall. As a result, Macao is often controlled by the easterly airflow, enjoying the "clear and refreshing autumn" weather.