Answer:Because the amount of water vapor in the air increases
Explanation:In humid climates, thunderstorms often cause heavier rain than general wintertime rainfall since moisture content in the air typically is higher in the spring and summer, and since air usually rises at a much more rapid rate within developing thunderstorms than in general winter systems.During very heavy rainfall, where all of the water in the atmosphere is often rained out, the water vapour content governs the amount of rainfall. The higher the humidity the greater the water vapour, and the more rain we're likely to see. HOPE THIS HELPS ^w^
