North American Monsoon Tracker
This site tracks the North American Monsoon (NAM) across the Southwest US and northern Mexico using ERA5 reanalysis: a 1991–2025 historical baseline, plus day-by-day tracking of the season currently underway. It follows the monsoon ridge, total column moisture, and how each day compares to the long-term normal — day by day, in 5-day blocks, and across the full season — built and maintained by the Climate Science Applications Program at the University of Arizona.
Following the 2026 season live? The daily map viewer updates most days the pipeline is run, but it’s built on preliminary near-real-time data (ERA5T and CPC’s early precipitation release) that can still be revised for a few months afterward — see Data & Methods for details. Looking for the most recent finalized season instead? Jump to 2025.
