This course explores how and why Earth’s climate comes about. We will not only introduce what a typical weather condition is over each region on Earth, but also how and why climate, statistic of weather, varies geographically and even temporally throughout the earth’s history. To understand how climate system works, this course discuss concepts of radiative transfer, fluid dynamics, and thermodynamics, with an emphasis of providing an overview of a few physical balances that are important for shaping and maintaining the surface climate: energy balance and its role in controlling temperatures; the hydrologic cycle and its role in controlling humidity and aridity; angular momentum balance and its role in controlling winds.