High or low temperatures at home were associated with higher risk of heart arrhythmia in elderly men, in a recent study from the Harvard Air Climate & Energy Center. Researchers analyzed electrocardiograms from 2000 to 2010 for 701 men from the Normative Aging cohort around Boston. Temperature at individual residences was obtained from satellite measurements (1×1 km resolution) calibrated through a network of ground-level weather monitors. The results indicated, in agreement with previous observations and after controlling for health, air pollution and other factors, that the risk of ventricular arrhythmias was associated with temperature in a U-shaped relationship. Compared to results using a single central weather station, the association was stronger: for a 1⁰ C increase in same-day temperature at home, the odds of an arrhythmia episode was 1.10 (1.04-1.17), compared to odds of 1.05 (1.02-1.09) for temperature at a central station. These results suggest that finer-scale predictions may be reducing bias from exposure error.