Evaporation plays a key role in this fun phenomenon. Evaporation is the transition of water from the liquid phase to the gas phase. The rate of evaporation depends on the temperature difference between the water and the air, and evaporation is more rapid in low humidity. Hot water is closer than cold water to evaporating, so your cup of near-boiling water is already close to becoming a vapor.
By dispersing the liquid water into a collection of liquid water droplets, you’ve increased its surface area, which also speeds evaporation. The combination of hot water, cold, dry air, and high surface area causes most of the tossed near-boiling water to evaporate before it hits the ground, and the tiny droplets that don’t evaporate will freeze into ice crystals while still in the air.
Location: Yellowknife, Northwest Territories, Canada
Temperature: -30 degrees Fahrenheit is -34.4 degrees Celsius.