Does the temperature during ice melting change?
Here is a naive interpretation, that may help you understand this phenomena.
In the presence of salt, water is attracted and &quot;wants&quot; to be adsorbed around $\ce{Na+}$ and $\ce{Cl-}$ ions. But this operation requires some energy for water molecules to separate the positive and negative ions. This is why the dissolution of $\ce{NaCl}$ in water is endothermic.
Now if you put salt in contact with ice, water in ice &quot;wants&quot; also to be attached to surrounding ions. But it cannot move. It first have to be a liquid. And there is no heat in the surroundings to make ice melt. Nature has found a way. Every piece of ice is divided in two parts. One part gives heat to the second part, that melts, makes water to dissolve the salt. But the remaining part has lost heat. So it gets cooler and cooler. The temperature of the remaining ice decreases from $0$°C to about -$20$°C.