Macau has a humid subtropical climate, with an average humidity of between 75% and 95%. The annual average temperature is around 22 °C (about 72 °F). July is the warmest month, and the temperature that month averages about 28.6 °C (about 83.5 °F). The coolest month is January, with an average temperature of 14.5 °C (about 58 °F). The rainy season extends from April to September, and during this period the island is victim to typhoons. Typhoon season extends from April to October.
Also read How to Plan a Tour of Macau from Hong Kong.
Spring in Macau is from March to May. It is warm during this time, and the average temperature during the day is 22 °C (71.6 °F). A T-shirt with long sleeves may be the best choice for you to stay comfortable. You'd be better to put on a sweater at night to stay warm as the temperature may drop a little.
Summer in Macau starts with June and ends with August. This season is the hottest among the four seasons in Macau. It is sunny most of the time and rains occasionally. The average summer temperature is 28 °C (82 °F) during the day, but may drop to about 25 °C (77 °F) at night. The sunshine is very strong, so sunscreen and an umbrella are necessary to protect you from getting sunburn. A dress or a mini-skirt is recommended when outdoors.
Macau's autumn lasts from September to November. The temperature is cooler than during the summer, and the average temperature this season is 23 °C (73.4 °F). Long-sleeve shirts and a sweater are recommended for this season. Autumn marks the busiest travel season of the year for Macau. Many tourists may visit Macau during the National Day holiday to appreciate the foreign-style buildings and to see the Ruins of St. Paul's Cathedral.
Winter in Macau is from December to February, when it is cold but not freezing. The average temperature during the winter is 15 °C (59 °F). A coat and a pair of jeans are needed for this season, which marks the low travel season. During the winter, the city is less crowded.