The temporal variation of accumulation and temperature in the Siberian Altai were investigated using a 86 m long ice core from Belukha glacier (49°48′26″N, 86°34′43″E, 4062 m a.s.l.), covering the time period 1816 to 2001. As temperature-sensitive parameters the melt percent profiles and the stable oxygen isotopes (δ¹⁸O) were evaluated, representing summer season and March to November temperatures, respectively. The accumulation record showed no long-term trend and only minor deviations of limited duration from the accumulation average of 0.5 m water equivalent/y (weq./y) were observed. In contrast, the two temperature proxies indicate a strong warming trend in the order of 1.6 ± 0.4°C and 1.7 ± 1.1°C over the last century, inferred from melt percentages and the δ¹⁸O record, respectively, and 2.5 ± 1.7°C since the mid-19th century, inferred from the δ¹⁸O record. This reflects an amplified regional climate response following the Little Ice Age (LIA) as compared to the Northern Hemisphere average, most probably caused by the strong continentality of the Siberian Altai region. The sudden onset of large melt features since 1988 indicates that the upper reaches of Belukha glacier are experiencing a change from the recrystallization to the cold-infiltration zone that now allows for multiannual percolation of meltwater, implying that the conservation of accumulation and geochemical properties, including those providing temperature proxies, is currently endangered.