The Weather Files Apr 2026

Speed and direction to estimate natural ventilation and infiltration.

Tools like the WeatherShift™ tool use climate model projections to adjust historical files for future decades (e.g., 2050 or 2080).

As the climate shifts, historical data (TMY) may become less representative of a building's future lifespan. Engineers now use to "future-proof" designs. The Weather Files

A primary source for thousands of international weather locations.

These are the most common files, created by statistically selecting the 12 most "typical" months from a multi-year period (often 10–30 years). Speed and direction to estimate natural ventilation and

The .epw (EnergyPlus Weather) format is a global standard developed by the U.S. Department of Energy . Other common versions include TMY3 and IWEC files.

These contain data from a specific, real-world year. They are essential for calibrating building models against actual utility bills or performance data. 2. Core Data Components Engineers now use to "future-proof" designs

A widely cited repository for updated TMYx files and climate change data.