The minimal temperature at which water can evaporate depends on the pressure at which it is being observed. The boiling point of water, which is the temperature at which water transitions from a liquid to a gas phase, varies with pressure. At standard atmospheric pressure (1 atmosphere or 101.3 kilopascals), water boils at 100 degrees Celsius or 212 degrees Fahrenheit.
However, if the pressure is reduced, such as at higher altitudes or in a vacuum, the boiling point of water decreases. In a vacuum, for example, water can boil at room temperature or even lower.
To specifically address the evaporation of water, it can occur at temperatures below its boiling point as well. Evaporation is a process where the liquid molecules gain sufficient energy to overcome intermolecular forces and escape into the gas phase. It can happen at any temperature, as long as the water molecules at the surface of the liquid have enough energy to transition to a gas.
In summary, while water typically boils at 100 degrees Celsius at standard atmospheric pressure, evaporation can occur at lower temperatures as long as the water molecules acquire sufficient energy to transition to the gas phase.