Our 12-inch latex balloons can generally stay afloat for 8 to 10 hours, or even longer, in an air-conditioned or room temperature environment. Temperature is one of the key factors that impact how long a balloon can stay in the air. As such, we do not recommend leaving your helium balloons floating outdoor for an extended period of time. Our best practice is to inflate your latex balloons with helium on the day of your party ONLY nearing the time of your balloons delivery or collection to ensure they remain beautiful and last for the duration of your party.