A lot of tourists visit Hong Kong during Christmas season, but the weather in the city this year has been set to be the warmest in 30 years. Wool hats, thick jackets, or scarves were unnecessary on this day as the Hong Kong Observatory expected a high of 24 degrees Celsius - which exceeded the highest temperature during this period over the past 30 years.

Hong Kong experiences the warmest winter solstice last Saturday, with a mean daily temperature of 22.2 degrees. The winter solstice or also known as dong zhi marks the longest night in the northern hemisphere, while in the Chinese lunar calendar, it symbolizes being thick in the winter.

But as the New Year approaches, Hong Kong's temperature is expected to drop to as low as 11 degrees Celsius after a warm Christmas. The Observatory said mercury would dip sharply as the year draws to a close.

Despite the warm weather condition on Christmas, more than 547,000 visitors arrived in Hong Kong on Sunday through 15 checkpoints and about 72,600 coming via two major pieces of infrastructure: the express rail link to mainland China and the cross-border bridge to Macau and Zhuhai, the South China Morning Post reported.

According to the Immigration Department, about 13.5 million Hong Kong residents and visitors were expected to exit and enter the city by air, sea, and land throughout the festive period. But, there are no holidays for some mascots representing various government departments, wherein they took the chance to deliver an educational message about waste reduction and home safety on Monday.

Environmental Protection Department's Big Waster posted a photo on its Facebook page featuring a Christmas tree made of old clothes. It calls the attention of the public to bring their trees to government collection points next weekend rather than dumping them in landfills.

Meanwhile, the fire service mascot's "Anyone" - who became a social media sensation recently - promotes electrical safety through a video introducing a junior "family member" to the public. Unlike his parents, the young boy wearing a blue hoodie showed his face, and he received a toy fire extinguisher for Christmas.

But amid Christmas celebration in other parts of the world, a lot of people were shocked and saddened due to a recent tsunami triggered by a volcanic eruption in Indonesia on Saturday night - more than 370 people were reportedly killed. Hong Kong's Humanitarian NGOs, like the Red Cross and then Plan International, asked the public to donate to rescue efforts while exchanging gifts and good wishes.