The Weather Files May 2026

Reliable weather data is available through several major repositories:

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

A primary source for thousands of international weather locations. The Weather Files

There are two primary categories of weather files used to analyze building energy demand and resilience:

Tools like the WeatherShift™ tool use climate model projections to adjust historical files for future decades (e.g., 2050 or 2080). Reliable weather data is available through several major

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

Speed and direction to estimate natural ventilation and infiltration. These contain data from a specific, real-world year

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