Extreme rainfall in Sumatra varies across coastal and mountainous settings, complicating comparisons of precipitable water vapor (PWV) and temporary vertical responses. This study examined their statistical correspondence with local rainfall during the November 2025 regional extreme event using global navigation satellite system (GNSS) precise point positioning (PPP) and Global Satellite Mapping of Precipitation (GSMaP). Observations from 13 stations in Aceh, North Sumatra and West Sumatra covered November–December 2025. PPP-estimated zenith total delays were converted to hourly PWV using co-located surface pressure and temperature. Daily vertical solutions were obtained separately with ambiguity resolution and final precise products, without temporal smoothing. Gauge-adjusted GSMaP rainfall was aggregated daily to identify each station’s local maximum within 24–28 November for event alignment. Vertical positions were detrended using the Theil–Sen estimator and expressed as changes (ΔUp) relative to inverse-variance weighted pre-peak means. At SAMP, nearest the radiosonde site, 117 PWV pairs yielded Pearson’s r = 0.957, root mean square error (RMSE) = 1.556 mm and mean bias = −0.347 mm. Median PWV enhancement and post-peak depletion were 4.54 and 8.61 mm, respectively. Median ΔUp was −10.97 mm on the day following the local rainfall maximum. Greater rainfall accumulation was associated with larger negative ΔUp (Kendall’s τ_b = 0.564), although station responses differed in timing and direction. These records support retrospective monitoring of PWV and temporary vertical changes around local rainfall maxima. Residual PPP bias and differences in sampling scale limit attribution of the vertical changes to rainfall alone.