The regional climate for the Texas Hill Country is classified as subtropical-subhumid. The mean annual temperature in the area is 18.7ºC and the mean annual rainfall is 30.2 cm. Precipitation maxima occur in spring and fall in response to frontal systems entering the region from the north that merge with unstable and moist air from the Gulf of Mexico.

The park maintains a weather station in the Johnson City District, where daily weather readings are manually collected. The Texas Forest Service maintains a weather station in the LBJ Ranch District. This collected data is used for fire weather forecasts.