BackgroundChildhood pneumonia remains a major public health concern worldwide, but the critical meteorological factors that contribute to it are unknown. ObjectiveTo investigate the relationship between childhood pneumonia and prenatal and postnatal exposure to meteorological factors to identify the critical factors and vulnerable timing windows. MethodsWe conducted a retrospective cohort study of 8689 preschoolers in China. We gathered information on personal factors, health status, and indoor environment through questionnaires. We considered meteorological factors including temperature (mean, maximum, minimum), diurnal temperature variation (DTV), relative humidity, wind speed, rainfall, pressure and sunshine during early life. Using multiple logistic regression models, we investigated the links between childhood pneumonia and early life exposure to meteorological factors. ResultsExposure to mean, maximum, and minimum temperatures was associated with childhood pneumonia in the first month and first trimester, with ORs (95% CI) of 1.32 (1.07–1.62), 1.26 (1.04–1.52) and 1.33 (1.08–1.64) in the first month, and 1.42 (1.12–1.81), 1.36 (1.08–1.71) and 1.47 (1.15–1.88) in the first trimester for per IQR increase in each meteorological factor exposure. Wind speed, rainfall, and sunshine exhibited significant associations with pneumonia during the first, second, and third trimesters, respectively. Exposure to various temperatures, DTV, relative humidity, rainfall, air pressure, and sunshine were linked to childhood pneumonia in the postnatal period, particularly in the previous year. The sensitivity analysis revealed that boys are more vulnerable to meteorological factors. Keeping dogs or plants may offer protection against the pneumonia risk of prenatal and postnatal meteorological exposure. ConclusionExposure to meteorological factors during both the prenatal and postnatal periods, especially in early pregnancy, was found to elevate the risk of childhood pneumonia.