The Arctic has one of the Earth's most sensitive and variable climates, yet due to its isolation and sparse population long-term observational data are rare. A field station at Toolik Lake in the northern foothills of the Alaskan Brooks Range has been recording a variety of meteorological and lake parameters since June 1988. From 1989 to 2007 there is no significant upward trend in surface temperature during the ice-free season at Toolik Lake, but anomalously warm summers show greater stability and longer mixing time scales when compared to anomalously cold summers. An understanding of the regional atmospheric controls on the mixing in Toolik Lake is essential to predict its response to Arctic climate change. Connections to frontal systems and seasonal temperature anomalies observed in previous studies suggest that both synoptic- and climate-scale patterns and variability are important. I will present my work to date on this topic, involving a preliminary characterization of the main synoptic-scale systems associated with mixing in Toolik Lake and the development of an algorithm to identify mixing events from an analysis of high resolution lake data.