tmy

**TMY (Typical Meteorological Year)**

The Typical Meteorological Year (TMY) is a standardized dataset used in solar energy and building design to represent the average weather conditions over a specific location. Developed primarily for solar resource assessment, TMY data provides a consistent reference for evaluating solar potential, system sizing, and performance predictions. Unlike actual weather records, which may vary yearly, TMY accounts for long-term climatological averages, ensuring reliability in engineering and planning.

TMY datasets are typically derived from historical weather records spanning at least 30 years, adjusted to reflect typical seasonal patterns. They include key meteorological variables such as solar irradiance (direct, diffuse, and global), temperature, humidity, wind speed, and precipitation. These datasets are often generated by national meteorological services or specialized organizations like the National Renewable Energy Laboratory (NREL) in the United States, the European Commission’s Joint Research Centre, or regional climate databases.

The primary advantage of TMY is its consistency, allowing engineers and researchers to compare solar installations across different locations without relying on fluctuating real-time data. It is widely used in solar photovoltaic (PV) system design, energy yield calculations, and the development of building energy models. While TMY does not account for extreme weather events, it provides a robust baseline for long-term performance estimates.

In recent years, TMY datasets have been supplemented or replaced by more advanced tools like the Solar Resource Assessment Tool (SRAT) or machine learning-based models, which incorporate satellite data and high-resolution weather forecasts. However, TMY remains foundational in traditional solar engineering and educational applications.