Suppose 3.0 cm of rain at 10°C falls on a rectangular region of dimensions 2.0 km x 3.0 km. How much energy was released when water vapor condensed to form this amount of rain?
Volume of H2O = .03 * 2000 *3000
mass = density * vol
Q = mL
You'll need to look up latent heat of vaporization for water.