Monsoon forcing dominates groundwater recharge reorganization across changing landscapes

Groundwater recharge replenishes groundwater resources and directly affects the water–food nexus and ecosystem sustainability. Spatial and temporal representation of continuous groundwater recharge and its linkage to climatic forcing, subsurface memory, and human water redistribution is essential for water management. Despite its importance, continuous recharge dynamics remain poorly mapped across large regions because observations are sparse and most recharge estimates are available at monthly to annual timescales. Here, we report daily estimates of groundwater recharge across India at 0.25° resolution for 2004–2025 using a storage-adapted master recession-curve framework applied to GRACE-assimilated groundwater storage, and characterize precipitation–recharge coupling and land-cover associations with recharge reorganization. We find that 74.1% of recharge occurs during the June–September monsoon. The ten wettest days provide 44.1% of annual precipitation, whereas the ten largest recharge days provide 21.0% of annual recharge, indicating that recharge is considerably less concentrated in time than precipitation. We also find that rapid daily-scale coupling between precipitation and recharge coexists with substantial temporal buffering, implying that atmospheric signals are reorganized by subsurface storage. This filtering produces four geographically coherent recharge regimes: strongly monsoon-pulsed, delayed post-monsoon, diffuse low-recharge and high-recharge responsive. The dominant temporal change is not a coherent increase in national recharge but a slight downward trend in the monsoon contribution, without a robust nationwide change in annual recharge or a shift in recharge midpoint. Precipitation variability explains much of year-to-year recharge magnitude and seasonal partitioning, whereas associations with land-cover change are weak and spatially inconsistent. These results identify India's groundwater renewal as monsoon-controlled but temporally buffered and regionally differentiated. More broadly, they show that groundwater replenishment can be reorganized within the hydrological year without a significant change in annual totals. By resolving when recharge occurs, how strongly it is concentrated, and how long it persists, these findings can help policymakers identify critical replenishment windows, target managed recharge interventions, and align groundwater abstraction and drought planning with region-specific recharge dynamics.