The Mill Race links upstream Lough Feeagh with Downstream Lough Furnace. The channel is short (200 metres) and shallow (<1 metre generally) and water temperatures measured here are very close to those measured on the surface waters of Lough Feeagh. This record has therefore, historically been used as a proxy for Lough Feeagh surface water temperature. Between 1960-2004, a Negretti paper chart recorder was used, and data were extracted for midnight each day. The chart recorder was checked sporadically against a mercury thermometer. From 2004 to 2009, a StowAway TidbiT temperature data logger from Onset (TBI32-05+37) was used (https://www.onsetcomp.com/products/data-loggers/tbi32-0537 ), and data extracted for time step nearest midnight. Between 2010 and 2017, temperature was recorded using an Orpheus mini water level recorder (https://www.ott.com/products/water-level-1/ott-orpheus-mini-water-level-logger-3/ ) and data extracted for time step before midnight.