In which phase change is energy being released to the surroundings?

Energy is released during phase changes from gas to liquid (condensation). When water vapor in a cloud condenses to form raindrops, it releases energy to the surroundings. This is because the gas phase (water vapor) has higher energy than the liquid phase (raindrops), and the transition to a lower energy state (liquid) releases the excess energy.

References:

Integrated Physical Sciences materials on condensation and energy release.

Concepts of energy changes during phase transitions.