The temperature of Jupiter varies. The temperature of the core is different than the upper atmosphere, and so on. Scientists do not have exact numbers for the various temperatures on the planet, but at the upper edge of the cloud cover, the temperature is thought to be -145 degrees C. On Jupiter the temperature increases because of atmospheric pressure, so as you descend temperature increases. Not far into the atmosphere the pressure is about ten times what it is here on Earth and the temperature is thought to be about 20 degrees C or average room temperature for Earth. Descend further and hydrogen becomes hot enough to turn into a liquid and the temperature is thought to be over 9,700 C. At the planet’s core scientists think that the temperatures could be as high as 35,500 C.
Jupiter is hot, massive, and contains plenty of hydrogen. So, why doesn’t it become a star? It isn’t nearly hot enough or massive enough. Jupiter would have to add about 80 times its current mass in order to become massive enough to ignite fusion. With that amount of mass, Jupiter would shrink in on itself(gravitational compression) and become hot enough to fuse hydrogen into helium. That is not going to happen any time soon since, outside of the Sun, there isn’t that much mass in our Solar System.
Storms and high winds are generated by cool air and warm air mixing here on Earth. Scientist think that the same holds true on Jupiter. The Galileo spacecraft observed winds in excess of 600 kph. One difference is that the jet streams that drive storms and winds on Earth are caused by the Sun heating the atmosphere. On Jupiter it seems that the jet streams are driven by the planets’ own heat. Storms on Jupiter are as out-sized as the planet. The Great Red Spot is a single storm that has been raging for hundreds of years. Other storms have been observed to grow to more than 2,000 km in diameter in a single day.
Scientists are striving to better understand the temperature of Jupiter in hopes that they will eventually be able to understand the planet. The Galileo probe helped and data from New Horizons went even further. NASA and other space agencies are planning future missions that should bring new data to light.
That’s hot, but Jupiter can never become a star, and here’s an article about how weather storms on Jupiter form quickly.