The western U.S. is experiencing increasing wildfire activity and warmer, drier climate conditions, with declining post-fire tree regeneration observed in many areas in recent years. Seedlings of mixed-conifer and subalpine forest species are sensitive to seasonal climate conditions, particularly in the first few years after a fire when many seedlings establish. Conifer seedlings may also be sensitive to microclimate, defined here as the air temperature and moisture near the ground where seedlings live. Microclimate conditions can vary dramatically at fine spatial scales and are affected by local topography and surrounding vegetation. To anticipate how forests will change in a future with more fire and warmer, drier climate, we need to understand how fire and climate interact to affect post-fire tree regeneration. The goal of this study was to quantify the impacts of wildfires on microclimate conditions relevant to conifer seedlings, and evaluate how fire severity and microclimate affect early post-fire seedling regeneration and survival in mixed-conifer and subalpine forests.