Helium balloons are affected by temperature. Please don't leave them in a hot car or trunk. If they get rained on and start to droop, don't worry – they'll float again when dry. Cold will deflate mylar balloons; warmer temperatures will reinflate them.
Likewise, what causes helium balloons to deflate?
Small light atoms can diffuse through tiny pores in stretched rubber much more easily than larger heavier molecules. However, helium balloons don't completely deflate when helium atoms diffuse out of the balloon, because some air molecules also move into the balloon.
Why does a helium balloon lose air?
Helium balloons are buoyant basically because helium has a lower density than air, and therefore the volume of air it displaces is heavier than its own volume. Hence, with time, helium leaks as its gas molecules are able to diffuse through the balloons' skins.
What temperature do helium balloons start to deflate?
It is a gel that goes inside a latex balloon, and then it will in fill in those pores so the helium does not escape. This is a NON-TOXIC gel. WHY DO FOIL BALLOONS LOOK LIKE THEY ARE DEFLATING IN THE COLD? – The helium gas starts to contract around the temperature of 50-45 degrees and will decrease in volume.