Breakdown: Why does rain make us sleepy?

Published: Sep. 26, 2021 at 9:50 AM CDT
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MEMPHIS, Tenn. (WMC) - Does rain make you sleepy? If so, you’re not alone! Many people say the sound of raindrops hitting the window can put them right to sleep. In fact, people often turn on recordings of the sound of rain to help them fall asleep at night. Why does rain have this effect on people?

Believe it or not, there are some pretty fascinating scientific reasons behind why rainy days seem like the perfect time to catch up on our sleep. This unusual sleepy feeling is partially linked to our own biological clocks and circadian rhythm. At the same time, our emotional state, the sound of the rain, the degree of humidity, and the lack of ultraviolet light can all contribute to the phenomenon.

The singular sound

According to, that distinctive pitter-patter of rain can contribute to the sleepy feeling. This is because rain creates something called “pink noise,” which is similar to white noise but differs in terms of energy distribution. Like white noise, pink noise is a mix of all the different frequencies that humans are able to hear, but the different distribution of energy across those frequencies allows it to be a more effective sleep aid.

Rain, rustling leaves, the wind, and even the sound of your own heartbeat all produce pink noise. Researchers in a 2012 study discovered that pink noise’s ability to reduce brainwaves is what made it so effective as a potential sleep aid.

Studies have found that when rain sounds enters people’s brain, brain unconsciously relaxes and produces alpha waves, which are very close to the state of brain when human sleeps.

The lack of light

Another reason you may be sleep is due to the lack of sunlight. When the human body is exposed to the Sun, it releases less melatonin (sleep-related hormone) and more serotonin (“feel-good” hormone). This makes people feel more alert and cheerful. The lack of light on a rainy day can have the opposite effect—people may feel drowsy or a little blue.

Decreased oxygen content in the air

Oxygen can stimulate the brain and make us feel refreshed. When it rains, there is more water vapor in the air, it results in lower air pressure and a relative decrease in oxygen content. In such a situation, brain begin to slack off, and people will feel sleepy.

However, because there is less oxygen in the air, you may still feeling weak and sleepy when you wake up; and may need to spend much more time to get out of bed.

Human activities are restricted

When it rains, there is a limitation on people’s activities. Many outdoor exercises can’t be done. For people who has nothing to do, sleeping is probably a good choice. Everyone likes comfortable state, and sleep is a kind of enjoyment.

The high humidity

The humidity of a rainy day also plays a part. When it rains, the air outside is heavy. As a result, the body has to work harder to maintain homeostasis. This can be tiring, leading many to seek a few extra minutes of shut-eye.

Now you know why the rain makes you so sleepy, but perhaps you’re still wondering how to combat this effect. The answer is simple: keep busy. Staying active, either physically or mentally, will help beat back boredom and keep your mind occupied and raise serotonin. Also, get some light, as much natural light as you can. It will lower your levels of melatonin.

If all else fails, and you have the time, take the nap.

March 12, 2018, is National Napping Day! (Source: file photo)
March 12, 2018, is National Napping Day! (Source: file photo)

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