Why can you hear the ocean so well at night?

Question

When I was a kid I used to worry we'd be hit by a tidle wave, even though the beach is a few miles away. Why can you hear it so well during the night?

Answer 1

During the day, the air transmits sound waves in all directions, including upwards.
Hoever, at night when the air is cooler and more damp, the sound waves are refracted horizontally, rather than vertically into the overlying drier air. Hence the sound waves travel more readily in a horizontal direction, and they seem louder. Of course, the absence of daytime noises also adds to the effect.

Answer 2

When the sun goes down at night the Earth releases its heat upwards toward space. This cools air masses. This cooling tends to move air as cooler air is heavier than warmer air (i.e. causing wind). So a dry dense cold front will move in and push the less dense and moist warmer daytime air away. It will also bring in more clouds and maybe even an inversion layer sometimes. Also this wind causes more wave action at night as oceans waves are impacted or created by wind. Also the moon affects the tides so at night when high tide moves in it brings the surf that much closer to your house.

Also with a cold dryer air mass, moist clouds, and a possible a moist inversion layer over the ocean at night a sound phenomena called "ducting" causes the sound waves of the surf to be ducted (i.e. directed) more horizontally under the air mass and more clouds in all directions including toward you. There may even be small short-duration sound echoes off of the denser air mass similar to audio reverb present too.

Have you ever noticed just before a rain storm that car's tires on the highway sound different? More reverb? This is also sound ducting in action.

Answer 3

Because at night, the air is cooler and less dense. The less dense air will transmit sound waves more readily than during the daytime.

Answer 4

And because they're less traffic noise

Answer 5

less noise.....most of us are sleeping and everything is peaceful and quiet, so sound travels further and can be more clearly heard....