Characterization of Regional Space Weather Conditions in Mexico During Solar Minimum 24/25: Baseline for Severity Scale Development

Abstract Using observations from the National Space Weather Laboratory's (LANCE acronym in Spanish) ground‐based network, we characterize regional space weather conditions in Mexico during the solar minimum 24/25 (2018–2020). Data analyzed include regional geomagnetic indices (the regional K index, Kmex, and H), ionospheric Total Electron Content (TEC) measurements, cosmic ray flux variations, and geomagnetically induced currents (GICs) in the national electric grid. Only weak to moderate geomagnetic storms were recorded, predominantly driven by Stream Interaction Regions. Regional geomagnetic indices revealed notable differences from global indices: in 49% of events, Kmex indicated stronger disturbances than Kp, and in 54% of events, H disturbances exceeded Dst values. Kmex max ranged from 2.3 to 6.3, corresponding to G2‐class storms or lower. GICs recorded during G1‐G2 storms ranged from 3.4 to 12.5 A, posing no immediate threat to grid stability. Ionospheric analysis showed low TEC values throughout the period, which were insufficient to disrupt satellite‐based systems. However, nighttime TEC depletions could compromise HF communications, particularly during June and July. A semiannual variation was observed in both minimum TEC values and occurrence times, with more frequent extreme low‐TEC events under reduced solar activity. Most low‐TEC events were uncorrelated with geomagnetic disturbances, highlighting the influence of neutral atmospheric dynamics. A revised operational threshold of TEC = % is recommended for detecting significant ionospheric variability during low solar activity. Cosmic ray observations detected one minor flux increase (26 August 2018) but no Ground Level Enhancements. These results establish a regional baseline for Mexico's space weather conditions, supporting the development of future severity scales and early warning protocols.