Current temperatures in microrefugia may persist longer than in nearby areas as temperatures warm. However, locating and measuring the contribution of microrefugia to thermal inertia in a landscape is challenging. We measured the thermal buffering capacity of microrefugia across a 40,000 km2 region of complex mountain topography by quantifying environmental lapse rate and solar radiation effects on air temperature in 0.1 km2 hexagons, a resource management‐relevant scale for climate adaptation. The greatest buffering capacity is −1.62°C, and only 2.8% of the region can buffer 1°C or greater. Historical loss of local cooling capacity is low, but by 2069 only 6.9%–11% of the region retains baseline temperature conditions. This thermal buffer index can find the most climate change‐buffered areas in lands identified as high priority for habitat conservation, wildlife corridors, and forest preservation. Other processes such as cold air pooling can complement our approach but depend on additional factors. Plain Language Summary Microrefugia are areas where local climate conditions may persist longer as temperatures warm because of their topographic features, which include the level of solar radiation and the elevation range they contain. Such areas are of conservation interest because their potential to retain current climate conditions longer, as global warming continues may be of particular importance for species with low dispersal capabilities. We modeled these features across a large mountainous region using 10 ha (25 acre) hexagons. The use of a standard size permitted inter‐comparison of 404,700 units to identify their relative capacity to retain their climate conditions from a temporal baseline of 1981–2010. We found that warming between the 1951–1980 and the baseline only affected about 14% of the region. However, by 2069, only 6.9%–11% of the hexagons still retained the conditions from baseline period, and by 2100 less than 1% of the landscape retains the baseline temperature conditions. The identification of hexagons with the most temperature buffering capacity can inform a number of land management and conservation strategies. We illustrate their use in frameworks for preserving vegetation types, landscape connectivity protection, and late seral forest preservation. Key Points Species with low dispersal capacity may depend on local microrefugia to persist as temperatures warm Over a 40,250 km2 area, we found that microrefugia buffering capacity at 10 ha scale is only retained in ∼6.9%–11% of the region by 2069 Quantifying local capacity to retain baseline temperatures can be used in a variety of natural resource strategies for climate adaptation