Fuego Volcano (14°29′N, 90°53′W, 3800 m) is the southernmost vent of the north-south–trending Fuego-Acatenango volcanic complex. A basaltic-andesite stratovolcano, Fuego has had more than 60 subplinian eruptions since A.D. 1524, making it one of the most active volcanoes in the world. Since 1999, Fuego has exhibited continuous low-level activity, which alternates between periods of lava effusion with Strombolian explosions and periods of discrete explosions with no lava effusion. We analyzed explosions recorded on a broadband seismometer and infrasonic microphones in June and July 2008. The explosions were identified through a combination of visual field observations and the examination of infrasound records. Acoustic waveform cross-correlation indicated a highly repetitive source appropriate for investigating temporal variations in the wave field. The primary focus of this study is a time period from 8 to 27 June 2008, which included the emergence of a new lava flow. Using seismic coda wave interferometry analysis of 159 well-recorded explosions, we detected short-term relative changes in the velocity structure ranging from −0.23% to 0.61%. This rapid variation may indicate minor fluctuations in volatile content. Variations in seismic and acoustic wave arrival time differences, which might result from changes in source depth, are attributed to wind speed variations.