Yes, the sun can indeed melt snow even when the air temperature is below freezing.
The key to understanding this phenomenon lies in the difference between air temperature and surface temperature. The reference states, "The sun is the main reason why snow can melt even when the temperature is below freezing." This is because:
- Direct Sunlight: Official temperature readings are not taken in direct sunlight. Direct sunlight can warm surfaces significantly, even on cold days, allowing them to reach temperatures above freezing.
- Ground Warming: Sunshine warms the ground, and this heat can then contribute to melting snow. The reference notes, "Sunshine can warm the ground to above freezing even when on some of the coldest days."
- Dark Surfaces: Darker objects, such as asphalt and rooftops, absorb more solar radiation than lighter surfaces. This means they can warm up much faster and more effectively, leading to snow melt even when the surrounding air temperature remains below freezing. The reference mentions that "Darker objects like asphalt and roof tops can warm easier as well."
Here's a breakdown:
| Factor | Explanation |
|---|---|
| Direct Sunlight | Warms surfaces, like snow, by direct absorption of radiation. |
| Ground Temperature | The ground beneath the snow can warm up to a melting temperature, especially when exposed to sunlight, melting the snow from below. |
| Surface Properties | Darker surfaces absorb more heat, raising their temperature and accelerating snowmelt, while light surfaces reflect light. |
In essence, while the air might be below 0°C (32°F), the radiant energy from the sun can heat the snow's surface (and the ground beneath it) to temperatures above freezing. This is why you often see melting snow even during cold weather.
