Environmental degradation is the largest public health challenge of the century and is likely to be exacerbated by climate change. This study undertakes a comprehensive examination of the health implications of environmental hazards in Cambodia, simultaneously addressing extreme temperatures, precipitation patterns, and air pollution. It leverages data from the Demographic and Health Surveys and satellite-derived metrics on temperature, precipitation, and fine particulate matter. The analysis identifies a positive association between temperature and the occurrence of diarrhea and cough among children and a nonlinear relationship between precipitation and these health outcomes. Furthermore, the study demonstrates that pollution significantly impacts cough incidence. To anticipate future trends, climate simulations are employed to forecast the incidence of child diarrhea in Cambodia under different climate and development scenarios. The projections indicate that diarrhea incidence could increase to 19 percent by 2040 without significant adaptation measures that would lessen the adverse impact of weather. For instance, the acceleration in toilet ownership over the last decade reduced diarrhea incidence by at least 1.2 to 1.4 percentage points. Nevertheless, the path ahead requires proactive efforts to improve sanitation and hygiene. The forecasts suggest that, without additional strategies to counter climate change's adverse effects, only universal toilet ownership would contain the climate-driven increase in diarrhea incidence expected by 2040.