average temperature of the ionosphere
| Filed Under: Space Leave a Comment. The ionosphere layer of the atmosphere overlaps the mesosphere and thermosphere and is the uppermost part of the atmosphere. The temperature of the ionosphere ranges from about 200K, or -73 ÂºC (-99.4 ÂºF) to 500K, or 227 ÂºC (440.6 ÂºF).So basically at the bottom it is 200K. At the top it is 500K.K is in Kelvin.he temperature of the ionosphere ranges from about 200K, or -73 ÂºC (-99.4 ÂºF) to 500K, or 227 ÂºC (440.6 ÂºF). So basically at the bottom it is 200K. At the top it is 500K. K is in Kelvin.