Ok, so let me get this straight.
Venus is 108,200,000km (67232362mi) away from the Sun and Mercury is 57,910,000 km (35983605mi), yet Venus is hotter? How does that even begin to make sense?
Well, here’s the answer!
The reason for this is all down to the planet’s differing atmospheres.
Mercury has a very thin atmosphere not unlike the conditions on the Moon. Venus on the other hand has a very thick dense atmosphere full of carbon dioxide which traps all the Sun’s heat in. This acts as a sort of super greenhouse effect as the Sun’s rays are radiated and absorbed by Venus.
With a thin atmosphere, Mercury’s temperature fluctuates wildly depending which side is facing the Sun. The planet’s climate can range from a quite hot 427 Celsius (801 Fahrenheit) at the height of day to a chilly -173 Celsius (-279 Fahrenheit) in the middle of the night. Conversely, Venus can reach temperatures of a scorching 467 Celsius (872 Fahrenheit).
There you go! Simple right?