What's the difference between cold air from Europe, North America and Australia and Siberian cold air from China in winter? Are they all wet and cold?

China's cold air comes from the inland, that is, Siberia, which is cold and dry due to the high pressure on the mainland.

The cold air masses in North America, Europe and Australia mentioned by the landlord mainly come from the sea, especially in Europe, and they are deeply impressed by the westerly belt and the warm current in the North Atlantic. Winter is mild and rainy.

Australia's low latitude, Sydney's climate type and I have passed the south, subtropical monsoon climate, mild and rainy winter.

The reason why the United States is wet in winter is that there are no mountains in the middle of the United States, and cold air from the northern part of the Great Plains can easily bring seawater inland.