An airmass is a large body of air that has relatively uniform temperature, humidity, and stability characteristics over a wide horizontal area. These characteristics are acquired when air remains over a source region for a sufficient period, allowing it to take on the thermal and moisture properties of the underlying surface. Once formed, an airmass can move from its source region and influence the weather of areas over which it travels. The nature of an airmass is commonly identified by its temperature (tropical, polar, arctic) and its moisture content (continental or maritime). Asia, being the largest continent with vast latitudinal extent and marked contrasts between land and sea, experiences distinct winter and summer airmasses that play a crucial role in shaping its seasonal climate. During winter, the dominant feature is the development of continental cold airmasses over the interior of Asia, particularly over Siberia and Central Asia. These regions experience intense radiational cooling due to long winter nights, clear skies, and snow-covered surfaces. As a result, a very cold, dry, and dense airmass known as continental polar (cP) or continental arctic (cA) forms. This airmass is characterized by extremely low temperatures, low humidity, and high surface pressure, giving rise to the Siberian High. The winter airmasses of Asia spread