What is the temperature for evaporation?

I have a very intelligent nephew who calls himself "handsome boy Kenneth". Intelligent, yes, for topping his level twice out of the three years so far in his primary school. Handsome, wells, I suppose beauty lies in the eyes of the beholder. Haha.

We had a conversation that goes,

Him: You know what's the average room temperature in Singapore in the evening?
Me: Room temperature?
Him: The lowest and the highest.
Me: (wild guess) 26 degrees.
Him: To?
Me: (wild guess) 32?
Him: Correct.
Me: Huh!? --> In total amazement with myself.

Moments later,

Me: What are you learning for science this term?
Him: Water.
Me: What do you know about water?
Him: Water has three states - liquid, solid and gas. Liquid is water, solid is ice and gas is steam.
Me: Ok.
Him: The boiling temperature of water is 100 degrees, and the melting and the freezing temperature is zero degrees.
Me: Ok.
Him: You know what is the temperature for evaporation.
Me: (confidently) 100 degrees lah.
Him: No, it is at all temperatures. My teacher teachs me one.


I mean like DUH! Of course it is at all temperatures.

Moral of the story:
You can never assume that you can learn nothing from a 10 years old and that you know everything at the back of your hand.

Kids are getting so smart nowadays.

And darn, isn't that a trick question. Hmph.