World Magnetic Model – High Resolution (WMMHR) available now and detailed in new report
NCEI and its partners are excited to announce the release of a new detailed technical report on the updated World Magnetic Model (WMM) 2025–30, which marks a key revision that occurs every five years. The accuracy of the WMM impacts everything from the U.S. Department of Defense’s (DoD) navigational tools to the performance of the GPS in cell phones. The latest version—the WMM2025—provides a key tool for modelling the change in Earth's magnetic field.
NCEI, with support from the Cooperative Institute for Research in Environmental Sciences (CIRES), plays a critical role in the development, maintenance, and distribution of the WMM. NCEI develops and distributes models of the geomagnetic field and maintains archives of geomagnetic data to further the understanding of Earth’s magnetism and its dynamic changes. NCEI also provides tools and services to visualize, access, and utilize the WMM2025 and other geomagnetic data products and models.
The WMM2025 provides more precise navigational data for all military and civilian planes, ships, submarines, and GPS units. This year, two versions of the model are being released. In addition to the WMM2025, the release includes the first-ever World Magnetic Model High Resolution (WMMHR), which features a spatial resolution of approximately 300 km at the equator, an improvement upon the standard spatial resolution of 3,300 km at the equator. Higher resolution provides greater directional accuracy, making this a significant improvement for users.
Upgrades
In addition to the introduction of the WMMHR, this release comes with some other key changes:
- The WMM predicts an intensification of the South Atlantic Anomaly (SAA) between 2025 and 2030.
- The WMM uncertainty analysis presented in the report has been updated with new data, resulting in a slightly revised error budget.
- The WMM report provides altitude ranges for varying levels of geomagnetic activity.
Partnerships
NCEI collaborates with partners to conduct research to better understand Earth's magnetic field, its variations, and its potential impact on Earth and its technologies. This research helps improve the accuracy of the WMM and contributes to the scientific community's broader understanding of the Earth's magnetic field and its various sources, from the core to electric currents in the near-Earth environment.
The WMM is the standard model used by the U.S. DoD, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO), and the International Hydrographic Organization (IHO) for navigation, attitude, and heading referencing systems using the geomagnetic field. It is also used widely in civilian navigation and heading systems.
The WMM report was sponsored by the U.S. National Geospatial-Intelligence Agency (NGA) and the U.K. Defence Geographic Centre (DGC); the WMM and WMMHR are produced by NCEI and the British Geological Survey (BGS).
