World Magnetic Model

Data Courtesy National Center for Environment Information

World Magnetic Model

The World Magnetic Model (WMM) is the standard model for navigation, attitude, and heading referencing systems that use the geomagnetic field. The WMM is also used for civilian applications, including navigation and heading systems.

A new version of the model is updated every five years to address changes in Earth’s magnetic field. The current version (WMM2025) was released on December 17, 2024, and will remain valid until late 2029.

The model is produced by the United States’ National Geospatial-Intelligence Agency (NGA) and the United Kingdom’s Defence Geographic Centre (DGC). NCEI and the British Geological Survey (BGS) jointly developed the WMM.

NCEI also developed the World Magnetic Model High Resolution (WMMHR), an advanced magnetic field model with more comprehensive data on the geomagnetic fields than the original World Magnetic Model. The WMMHR uses a set of forecasting models to provide detailed coverage of the main field and secular variation up to degree 15.