Macau has a humid subtropical climate, with average relative humidity between 75% and 90%. Similar to much of South China, seasonal climate is greatly influenced by the monsoons, and differences in temperature and humidity between summer and winter are noticeable, though not as great as inland China. The average annual temperature of Macau is22.7 °C (72.9 °F). July is the warmest month, with average temperature being 28.9 °C (84.0 °F). The coolest month is January, with a mean temperature of15.0 °C (59.0 °F).
Located on China's southern coast, Macau has ample rainfall, with average annual precipitation being 2,120 millimetres (83 in). However, winter is mostly dry due to the influence of the vast Siberian High affecting much of East Asia. Autumn in Macau, from October to November, is sunny and still pleasantly warm with low humidity. Winter (December to early March) is generally mild with temperature above 10°C most of the time, although it could also drop to below 5°C at times. Humidity starts to increase from late March. Summer is very warm to hot (often rising above 30 °C (86 °F) at daytime). The hot weather is often followed by heavy rain, thunderstorms and occasional typhoons.
(taken from Wikipedia)