The Arctic has a disproportionately large response to the radiative forcing of climate compared to the rest of the globe. Proglacial lakes serve as archives of past climate variability, trapping sediment transported by glacier and snowmelt runoff. The goal of this research is to generate a high-resolution climate record for the past millennium in the Arctic in order to place recent warming in a long-term context. This study uses 239+240Pu-dated varved sediments from a proglacial lake on northeast Baffin Island, Arctic Canada to generate a 1000-year-long annual-resolution record of climate. Varve thickness is positively correlated with July-August-September temperature measured at Clyde River, 70 km to the north (r = 0.46, p < 0.001). A stronger correlation results when three-year averages of varve thickness and temperature are compared (r = 0.66, p < 0.01). We therefore interpret the subdecadal variability and trends in varve thickness to partially represent summer temperature. The coolest Little Ice Age temperatures occurred in this record from 1575-1760 AD and were approximately 1°C cooler than today. Pre-20th century warmth occurred during two intervals, 950-1150 AD and 1375-1575 AD, and was approximately 0.5°C cooler than today. This varve thickness record contains variability similar to that reconstructed elsewhere in the eastern Canadian Arctic. This high-resolution record expands our understanding of arctic climate during the past millennium.