Nice Question Joshua,
At 4-H Summer of Science Headquarters or (HQ) the thing we love the most is a GREAT QUESTION and this one is a super good one.
Joshua asked: Why is it when it is hot and muggy, you feel more heavy then when it is cold?
For the answer from Roz Zurko click read more below.
The term "heavy air" is used often when discussing hot and humid . People say you can "cut the air with a knife," referring to its heaviness. However, the air people often refer to as heavy, isn't really the most moist type.
Read more: What Is Heavy Air? | eHow.com http://www.ehow.com/about_5553976_heavy-air.html#ixzz1QgOmxcag