Why Do Helium Balloons Deflate In The Cold?
When helium is exposed to cold temperatures, its molecules move more slowly and the pressure inside the balloon decreases. This causes the balloon to deflate as the helium gas molecules are not able to maintain their usual volume and pressure due to the cold temperature. Additionally, the colder air outside the balloon is denser and more likely to seep into the balloon, displacing some of the helium molecules and further causing the balloon to deflate.