First, the temperature. The latitudes of Sanya and Beihai are similar, but there are still some differences. Sanya has a tropical climate. Historical temperature shows that the average temperature in Leng Yue, Sanya is around 20 degrees, and winter is the dry season in Sanya, so it seldom rains here in winter. Relatively speaking, the air humidity is relatively small, which is good for the elderly.
The North Sea has a subtropical climate. Historical data show that the lowest average temperature in the coldest month in Beihai is around 10 degrees, which is a little low for young people, let alone the elderly. Moreover, the winter rainfall in Beihai is much higher than that in Sanya, and sometimes it rains.
Therefore, the weather here is still relatively humid. Coupled with the cold air, the elderly can't stand it, but the temperature lasts for a short time, and southerners are ok. The south is inherently wetter than the north, which is suitable for southerners to support the elderly.