why does venus experience so little temperature changes compared to Mercury? which of these two planets is hotter and I? Solution Venus has a very thick atmosphere predominantly consisting of CO2. Tje pressure on its surface is 91 times the pressure on Earth\'s surface. CO2 is a greenhouse gas which allows incoming radiation but prevents outgoing radiation. The atmosphere retains the sun\'s heat, which boosts the temperature, and then evenly distributes it planet-wide, making the poles about as hot as the equator. Mercury, while closer, has such a thin atmosphere,which is barely present; Like the moon, in sunlight, the surface heats up rapidly, but in shadow, it cools down rapidly. The night side of Mercury is *very* cold, while the daylight side is very hot. Overall, Venus is hotter than Mercury, but the hottest points of Mercury are hotter than Venus..