This study investigates the performance of a double-beam piezo-magneto-elastic wind energy harvester (DBPME-WEH) when exhibiting a galloping-based energy harvesting regime under wind excitation. The DBPME-WEH comprises two piezoelectric beams, each of which supports a prism bluff body embedded with a magnet at the tip. The magnets are oriented to repulse each other to introduce a bistable nonlinearity. Wind tunnel tests were conducted to compare performances of the DBPME-WEH and a double-beam piezoelectric wind energy harvester (DBP-WEH) that does not comprise the magnet-induced nonlinearity. The results reveal that compared to the DBP-WEH, the critical wind speed to activate the galloping vibration of DBPME-WEH can be reduced up to 41.9%. Thus, the results corroborate the significant performance enhancement by the DBPME-WEH. It can also be found that the distance of the two magnets affects the performance and the distance that achieves the weakly bistable nonlinearity is beneficial to energy harvesting in reducing the critical wind speed and improving the output voltage.