The heat would make no difference, but the atmosphere would increase the weight.
Carbon dioxide traps the heat in the atmosphere of Venus and prevents it from escaping in to space (Venus contains a great amount of Co2 in its atmosphere). That's why, Venus is known as the hottest planet in the Solar System.
You would seem to weigh less on Mars or on Venus than you do here on Earth, although the environment of Venus would be intolerable because of the high temperature and extreme pressures. On Mercury you would weigh much less, but the heat there is intense.
The "greenhouse effect."
Carbon dioxide.
Venus has a very thick carbon dioxide atmosphere, which traps the heat from the sun.
Greenhouse effect. The same effect that keeps Earth warmer than if there would be no atmosphere: without an atmosphere, the average temperature on Earth would be below zero Celsius.
Carbon Dioxide. There is considerable sulphuric acid in Venus's atmosphere, too, but it is predominately Carbon Dioxide.
Venus
carbon dioxide and fu
in venus the atmosphere traps in heat to make it very hot and cloudy and it rains acid on venus.
Venus is hotter than Jupiter because Venus has a thick atmosphere that traps heat from the sun, creating a strong greenhouse effect. In contrast, Jupiter is a gas giant with a much greater distance from the sun and doesn't have a surface that can retain heat like Venus does.
Mercury is less hotter than Venus because it has a thin atmosphere and the heat that is attracted during day time goes away at night and the temperature becomes -170 degrees while Venus has a thick atmosphere and does not allow heat to pass.