Fluid dynamics is the foundation that underpins weather and climate. Fluids govern physics around us from weather patterns, to the ocean's waves, to glaciers: all of which affect human life, society and habitability. This is a crash course in the fluid dynamics governing the Earth's atmosphere, ocean and cryosphere. In the first half, we introduce fundamental concepts in fluid dynamics, including viscosity, momentum balance and waves. The second half of the course discusses applications to geophysical flows including rotating geophysical flows and turbulence.