Representative climate data are important for comparing computer simulations of building designs and their resultant energy needs. In 1969, recognizing a growing interest in such data, ASHRAE Technical Committee 4.2--Weather Information (TC4.2), commissioned development of hourly weather files. The resulting data for 51 locations in the U.S. and Canada are called Weather Year for Energy Calculations (WYEC).

In 1988, TC4.2 initiated a major revision of the WYEC files. This effort was limited to adding the 26 Typical Meteorological Year (TMY) hourly weather files to the original WYEC database and making many significant improvements and enhancements to the available data elements. Specifically, the need existed to use a consistent time convention, correct excessive solar radiation values, screen the meteorological data for physically impossible values, provide model estimates of additional solar irradiance and illuminance values, and include data quality indicators.

The work of revising and improving the WYEC database was done at the National Renewable Energy Laboratory (NREL). The resulting set of 77 revised and corrected hourly weather files are known as WYEC Version 2 or WYEC2 files.

This paper describes the NREL production of the WYEC2 data files for ASHRAE.

Units: SI