which planet shows the largest variation of day and night temperatures?
In summer, when it is at its closest approach to the sun, the daytime temperature can reach 465 degrees Celsius (870 degrees Fahrenheit). At night, the temperature can drop to -184 degrees Celsius (-363 degrees Fahrenheit). This happens because the planet has no atmosphere to retain heat. The temperature on Mercury's surface fluctuates more widely than that on the surface of any other planet. It can vary by 649 degrees Celsius (1,168 degrees Fahrenheit).