With an average temperature of minus 234 degrees Fahrenheit (minus 145 degrees Celsius), Jupiter is cold even in the warmest weather. Unlike the Earth, whose temperature changes as you approach or move away from the equator, the temperature on Jupiter depends on the height above its surface. This is because the heat does not come from the Sun, but from the bowels of the planet. On Jupiter, there is no clear difference between the seasons, as on Earth.
Jupiter doesn’t seem to have any distinct boundaries at all. The surface of Jupiter is also a conditional thing. For a certain conditional “surface”, scientists determine the lower boundary of its atmosphere at the point where the pressure is 1 bar. The temperature of the atmosphere on Jupiter, like that of the Earth, decreases with height until it reaches a minimum.
According to direct measurements by the Galileo lander, the upper level of opaque clouds was characterized by a pressure of 1 atmosphere and a temperature of −107 °C; at a depth of 146 km – +153 °C. Galileo also found “warm spots” along the equator. Apparently, in these places the layer of outer clouds is thin and one can see warmer inner regions.
The lander entered Jupiter’s atmosphere in December 1995. He worked in the atmosphere for about one hour, descending to a depth of 130 km.
Jupiter heating sources
Jupiter’s distance from the Sun averages 484 million miles (778 million km), and it receives little heat from the star, although it does contribute.
Approximately 1361 watts per square meter of solar energy falls on Earth at the upper boundary of the atmosphere. Jupiter has only about 50.5 watts per square meter.
Most of the heating of the giant planet comes from within the planet itself. Beneath the surface, the convection of liquid and plasma hydrogen generates more heat than the sun. This convection keeps the massive gas giant warm enough to keep it from becoming an icy world.