The winter monsoon in China comes from Eurasia in the middle and high latitudes, that is, Siberia, which is the coldest place in the northern hemisphere in winter. It is located in the mainland and has a dry climate, so the northwest monsoon in winter is cold and dry. The northeast monsoon in South Asia comes from the middle-low latitude continent, so it is not as cold as the northwest monsoon.
The main summer monsoon in China includes the southeast monsoon from the middle and low latitude Pacific Ocean and the southwest monsoon from the Indian Ocean near the equator. They are warm and humid in nature because they come from low-latitude oceans.