The growing demand for sustainable power sources for microelectronics and wireless sensor networks has intensified research into ambient energy harvesting. This study introduces an Adaptive Wind-Speed Piezoelectric–Electromagnetic Hybrid Harvester (AWS-PEMH) that combines a novel tilt-adjustable slide-rail adaptive unit with one piezoelectric module (PEH) and two electromagnetic modules (EMH-1, EMH-2) to achieve a low startup wind speed, a widened effective operating range, and promising operational stability. Unlike conventional spring-based adaptive harvesters, the AWS-PEMH employs a novel tilt-adjustable slide-rail mechanism utilizing gravity as a fatigue-free restoring force. This springless design minimizes initial rotational resistance, enabling an exceptional startup wind speed of 1.6 m/s. As wind speed increases, centrifugal force engages both modules synergistically. Empirical investigations reveal a beneficial friction-induced hysteresis during mode switching, acting as a mechanical low-pass filter to prevent high-frequency chattering under fluctuating natural winds. By staggering discrete resonant peaks via a multi-mass piezoelectric array, the continuous operational bandwidth is effectively broadened to 4.1 m/s (sustaining > 10 mW integrated output). Discrepancies between ideal models and empirical data are systematically resolved through parameter sensitivity analysis and the incorporation of Duffing-type nonlinear magnetic hardening dynamics. Electrically, an independent dual-path power management topology effectively decouples the modules, achieving a high conversion efficiency even under low-input-power conditions (< 5 mW) typical of weak winds. The fully enclosed prototype yields a peak power of 38 mW (volumetric power density of 22 μW/cm3) and demonstrates stable short-term performance with negligible degradation after a 72-hour continuous test (7.128 × 105 cycles). Validated by rooftop field tests, the AWS-PEMH provides a highly resilient power solution for distributed outdoor sensing.