Heat-related morbidity and mortality are recognized threats to public health. Given the abundant evidence linking extreme heat to morbidity and mortality, many communities have implemented heat communication plans, warning systems and/or heat response plans aimed at reducing the public health burden of future heat events. Recent evidence from the Northeast Heat Collaborative in New England, suggests that, while extreme heat events (i.e., heat waves) are associated with an increased risk of death, the absolute number of ED visits attributable to more moderate temperatures can be much larger. In recognition of these important adverse health effects associated with moderate temperatures, collaborative efforts in New England have succeeded in lowering the heat index threshold that the National Weather Service (NWS) uses to issue excessive heat advisories. There is currently no evidence-based optimal strategy for preventing morbidity and mortality due to moderate summer heat, as the issue receives relatively little attention in scientific literature. Public health and emergency preparedness officials should develop localized collaborative risk communication strategies, tiered warning systems, and heat response plans that address both extreme and moderate heat. Strategies should focus on both the direct impact of heat on health as well as the important, but less obvious, role of moderate temperature in exacerbating pre-existing health conditions. Current research efforts are focused on defining the role of public health in responding to moderate heat, developing effective messaging that focuses on both the direct and indirect impacts of heat, and establishing clear communication channels between public health and emergency response professionals at the state and local level.