Daytime temperatures may reach above freezing, but because the planet is blanketed by the mere wisp of an atmosphere,the heat radiates back into space. 白天，那里的溫度可以達到零上，但因為包裹火星的大氣層極為稀薄，熱量又會(huì )輻射回宇宙中。
This afternoon's sunshine could nudge the temperature above freezing. 今天下午的陽(yáng)光可使溫度達到冰點(diǎn)以上。
On a cloudless night, frost may form on horizontal surfaces even when the temperature of the air is above freezing. 在晴朗的夜晚，即使空氣的溫度在冰點(diǎn)以上，地平面上也能結霜。
