A small liquid particle. The size of droplets encountered in the atmosphere extends over a wide range; e.g. liquid aerosol solutions which make up the fine particle fraction of continental tropospheric aerosol are usually $2\text{μ}\text{m}$ in diameter. Cloud water droplets usually have diameters in the range of $5-70\text{μ}\text{m}$, while rain droplets commonly have diameters ranging from $0.1-3\text{mm}$.