PCMDI has developed a powerful data analysis tool for geophysical scientists. This tool, the Climate Data Analysis Tool (CDAT), is based on Python, an object oriented scripting language. It gives the user access to a wide variety of applications such as: database management, standard (and user-defined) mathematical and statistical functions and visualization. The complete integration of CDAT with Python gives the user access to a totally open system that is not restricted to the use of PCMDI-developed software. We demonstrate some of CDAT's many, yet easy, capabilities by means of an interactive demonstration