Background: Global temperature and the frequency of extreme weather events are projected to increase and affect indoor exposure to outdoor particulate matter (PM); however, no studies have quantitatively examined the effect of climate change on particle infiltration and indoor PM exposure. Obective: To quantify the relationship between future changes in ambient temperature and fine particle (PM2.5) infiltration in the Greater Boston area. Methods: We assembled a large database of outdoor and indoor PM2.5 data from 340 homes, and used the indoor-outdoor sulfur ratio (Sr) as a surrogate for PM2.5 infiltration. We employed linear mixed effects models to examine the relationship between Sr and ambient temperature for all homes in the database and a subgroup of naturally ventilated homes. We used projected temperature data from 1981 to 2000 and 2046-2065 to predict future changes in Sr. Results: The summer-winter difference in Sr was calculated to be 30% and 54% for all homes and in the naturally ventilated subgroup, respectively. The largest future difference in S-r (21%) was linked to differences in prevalence of air conditioning. Furthermore, Sr was predicted to increase by 7% for naturally ventilated homes and 2% for all homes in summer, corresponding to an average increase of 2-3 degrees C in future temperature. Conclusions: We found that increases in future temperature due to climate change will be associated with increased PM2.5 infiltration, particularly in summer. The predicted temperature-related changes in S-r can be used to characterize future health risk due to elevated indoor PM2.5 exposure through increased particle infiltration. (C) 2016 Elsevier Ltd. All rights reserved.