Why does it snow in winter?

Snow occurs in winter due to a combination of factors including low temperatures, moisture in the air, and the presence of precipitation. In winter, the Earth's axis tilts away from the sun, causing sunlight to be spread over a larger area, resulting in lower temperatures. When the air temperature drops below freezing point (0 degrees Celsius or 32 degrees Fahrenheit), water vapor in the atmosphere condenses directly into ice crystals instead of remaining as liquid droplets. These ice crystals then come together to form snowflakes.

The moisture necessary for snowfall usually comes from evaporated water from oceans, lakes, and rivers. As the cold air mass moves over the warmer bodies of water, it absorbs moisture and becomes saturated. The saturated air cools down further, causing the formation of snowflakes. These snowflakes eventually fall to the ground as snow when the atmospheric conditions are favorable, such as when there is enough moisture and atmospheric instability for precipitation.

Therefore, the combination of freezing temperatures, moisture, and precipitation is what leads to snowfall in winter. It's a beautiful phenomenon that brings joy to many people and also has important impacts on ecosystems, agriculture, and water resources.