Deck the Charts: Christmas, Streaming, and the Return of One Catalog

Popular music charts changed what they measure when streaming replaced sales. A purchase-based chart records acquisition, and a purchase extinguishes the demand it registers; a streaming chart records use, and every play counts anew. Demand that recurs on a fixed schedule for a fixed repertoire was therefore invisible to the sales-era instrument and fully visible to its successor. Using daily Spotify Top 200 charts for Germany (2017-2025) matched to audio features, and weekly chart data spanning 1977-2025, we show that seasonality in the acoustic character of charted music is a phenomenon of the streaming era: absent before 2015, growing steadily since, and dominated by Christmas. On December 24 streaming volume reached 4.6 times the annual daily mean in 2024, up from 2.9 in 2017, and the charts shift sharply toward high acousticness and low energy. The pattern is selective across twenty holidays: Easter, which shares Christmas's family character, produces no acoustic effect at all, while New Year's Eve moves the charts in the opposite direction. The December peak is carried by a fixed and aging catalog, but age is that catalog's property rather than its cause: on an ordinary day old recordings are less acoustic and more energetic than contemporary releases, so a shift in age composition alone would move December the wrong way. The December component of any series built from these charts therefore reflects the recirculation of a fixed historical catalog rather than contemporary listening, with direct consequences for the seasonal adjustment of music-based sentiment indicators.