This document presents the user guide for the Long-Term Pavement Performance (LTPP) online Climate Tool. This Tool provides easy access to climatic data extracted from the National Aeronautics and Space Administration Modern-Era Retrospective Analysis for Research and Applications (MERRA) database. The MERRA dataset is very large and the Tool provides access to this large dataset in an intuitive and easy-to-use format.

The LTPP Climate Tool provides the option to download historical climate data from 1979 to the present. The climatic attributes available are temperature, precipitation, humidity, wind, and solar. The data are available globally in hourly, daily, monthly, and annual increments.

This new Tool provides pavement and bridge engineers and other users with a simplified method for the extraction and processing of worldwide climate data for infrastructure engineering and other applications.