The hottest planet in the solar system?

Mercury: the lowest is -86℃ and the highest is 634.5℃ (no atmosphere, large temperature difference between day and night).

Venus: The lowest temperature is 465℃, the average temperature is 475℃, and the highest temperature is 485℃. (There are dense carbon dioxide clouds, and the surface insulation effect is good)

On extreme high temperature mercury

The average maximum temperature of the wheel is Venus.

These are from the surface of the earth. If the center of the hottest star is Jupiter (280 thousand degrees Celsius).