Why do even the SLIGHTEST sounds become easier to hear early in the day than later in the evening?

Question

Just curious... It became wierd to me when I noticed in the morning I woke up at 5:00 AM and nobody was awake... I dropped my pencil and it seemed like SOO loud! ahahaha... anyways... it wouldn't seem that loud in the evening I know... EVEN IF EVERYONE WAS QUIET! is there a reason everything is quieter and easier to hear in the morning than in the evening?

Answer 1

Some things that would be likely to affect how distinct sounds are in the morning compared to the evening include the air temperature, whether people are awake, animal sounds, and traffic sounds.

The early morning is the coolest time of the day, and I'm pretty sure that cooler air carries sound better because of its higher density.

People being awake or asleep makes a big difference, but I notice you think it wouldn't make a difference. Well, what about animal noise? Whenever I get up early, sometimes I'll sit outside and enjoy the peace and quiet. However, right before the sun starts to come up, all of the birds start chirping. This phenomenon takes place over about 15 minutes and is therefore quite recognizable.

Another factor you have to consider is machinery and daytime traffic that you don't hear directly, but certainly contributes to the ambient noise in your vicinity. What about all of the home AC units turning on across town once the sun starts heating things up again? The air itself starts moving too in currents caused by the sun's heat.

All of these things are going to affect and increase the ambient noise, or white noise, drowning out sounds that take place at other times of the day.

One last thing. There are more late night people than early risers. Even if your whole family goes to bed on time, it doesn't make that much of a difference in the average noise caused by the rest of everyone who's still awake. Just like temperature, I believe that overall population activity will graph in a similar way, showing the lowest values during the early morning.