Question

What is the relationship between temperature and altitude in the stratosphere?

Answer 1

In the stratosphere, the temperature actually increases when the altitude is higher. The increasing temperature is due to the absorption of UV rays which are by the ozone layer, I believe.

Answer 2

Stratosphere is said to be very agitated as a lot of phenomena take place there, like thunderstorms, heavy rains, etc.
Hence temperatures can vary from very high to very low.