In Chinese culture, snow (雪 (xuě)) holds a rich, dualistic meaning that goes beyond just a weather event. On one hand, snow is a powerful symbol of purity, beauty, and tranquility. The blanket of white is seen as cleansing the land. This aesthetic is deeply woven into classical poetry and art, often paired with the image of plum blossoms (梅花 méihuā), which bloom in the cold and symbolize resilience and perseverance in the face of hardship. On the other hand, there is a very practical and auspicious view of snow, encapsulated in the famous proverb: 瑞雪兆丰年 (ruì xuě zhào fēng nián) - “A timely snow promises a good harvest.” The snow blanket protects winter crops like wheat from the harsh cold and provides essential moisture for the spring planting season. This agricultural connection contrasts with the common Western view of snow, which is often linked to holidays like Christmas, “snow days” off from school, or purely recreational activities. While Chinese people certainly enjoy playing in the snow, the deep-rooted cultural association with a prosperous future is a unique and important aspect of 下雪.
In daily conversation, 下雪 is used matter-of-factly to describe the weather. It's a neutral term, and its connotation depends entirely on the context.
The term itself is neither formal nor informal and is appropriate in virtually any situation where you'd talk about snow.