Using AFM, X-ray, and neutron reflectometry, James et al. uncovered that a droplet grown (∆m ≥ 0 mass increase) in a given humidity ambient on monolayer water film remains ice-like, hydrophobic till 323 K (∆m = 0). In contrast, evaporation occurs at 338 K (∆m < 0). The growing droplets exhibit superheating in melting Tm = 273 K and supercooling in evaporating, TV = 373 K under ambient pressure. Similarly, a droplet having a higher surface curvature took 70 sec longer to freeze at 269 K .