Why does refrigerated water (12°C) freeze when poured into a glass at ambiant temperature (30°C)?

Question

I live in Sub-Sahara Africa. This phenomenon is frequent. The refrigerator temperature is standard (in °C) so the water is NOT frozen. The water is cool, not ice cold when taken from the fridge. The ambiant temperature is "normal" for this region of Africa (in °C not F). Thank you very much, Sarah

Answer 1

This is fascinating. I could never imagine that it is even possible. Please don’t take my word for it (see reference below).
It is hypothetically possible for the water to form ice crystals if you could somehow force it rapidly evaporate. During phase change a heat is being required to transform liquid into gas (latent heat of evaporation) that could take energy and thus reducing the water temperature. However water is a very good conductor of heat, so no dice, it will not work. .