Warmer Weather, Abundant Sound

Well, not exactly more sounds, but it seems to me as the weather gets warmer, I can hear more sounds. I have my window open right now and I can hear the starlings in the garden below; the hiss of the buses as they lower their hulls for the elderly; the doppler of cars rolling by; the children screeching in the playground; the planes overheard, their engines thundering in descent; the rattle of some mechanical mishap... And on the face of it, it seems like there are more people outside now, but that's not all - the quality of sound is different. And when you think about it, it makes sense, there must be an effect on sound waves as they travel through molecules thick and thin.

Some quick Googling reveals that sound waves travel farther in warmer temperatures since the molecules are vibrating more. Sound depends on these vibrations to get from the horn on a car to the drum in my ear. This speed of sound calculator clarifies a bit: http://www.sengpielaudio.com/calculator-speedsound.htm

At 0 Celcius sound travels at 331.5 m/s / the impedance is 428.3 (not sure what measurement but we'll look a the number for now)
At 30 Celcius sound travels at 349.2 m/s / the impedance is 406.6

Intriguing. Not only does sounds travel faster in warmer temperature, but to me it looks like it might travel further because of the lower impedance! So there you have it, next time you wonder why it seems like things are louder in the Summer it may not just be because there are people around to enjoy the weather, but the molecules are partying it up too and they're relaying the message.