New particle formation and growth have long been recognised as important processes in the atmosphere, with major influences on meteorology and climate, but a comprehensive understanding of the processes has proved elusive. This letter introduces a model considering the multiphase effects of temperature on the kinetics of growth through both condensation and diffusivity, and finds that these create opposing phenomena, moderating the growth rates and helping to reconcile atmospheric and laboratory data previously considered inconsistent. This approach may become key in better understanding and predicting particle growth in the atmosphere.