Despite being farther away from the sun than Mercury, Venus has a much warmer temperatures. What accounts for Venus is temperature being higher than mercury's?

Venus has a much thicker atmosphere

Explanation:

The main reason for Venus having a much higher temperature than Mercury is due to the difference in atmosphere. Venus has a much thicker atmosphere, this extra thickness allows Venus more heat to get trapped, through the greenhouse effect which keeps Venus much warmer than Mercury. If Venus were to lack this atmosphere it would be much colder than the average temperature in Mercury, which is 333 degrees Fahrenheit.