<p>A physical explanation makes no sense at all as we know the temperature continues to fall. In addition, all the surfaces that emit IR at night also do during the day, as IR radiation is just a function of temperature.</p>
<p>The answer has to be local environmental, biological or psychological.</p>
<ul>
<li><p><strong>Local environmental</strong> - humidity can rise at night, and air currents fall reducing evaporation and thus raising perceived temperature.</p>
</li>
<li><p><strong>Biological</strong> - In a poorly ventilated room, humidity can rise at night and body warmth can also raise the temperature.</p>
</li>
<li><p><strong>Psychological</strong> - Your sensitivity to heat may be higher.</p>
</li>
</ul>

CC BY-SA 4.0
2022-08-25T04:30:51.763Z
2023-02-01T14:44:07.980Z
2023-02-01T14:44:07.980Z
Peter Higgins
<p>Could the answer be that the temperature falls at night compared to what it was during the day? It is unlikely to stay the same temperature during the day and night on a regular basis. The drop of temperature would increase the relative humidity, compared to the day, and so it will feel 'muggier' at night, which might lead to you thinking it feels hotter. The vague idea I'm proposing is that the '<a href="https://www.weather.gov/ama/heatindex" rel="nofollow noreferrer">heat index</a>' increases at night or at least stays similar. Your brain may then expect it to feel cooler at night and so notice the heat more.</p>
<p>For example if it's 90°F and 55% humidity then the heat index is 97°F. If at night these readings change to 84°F and 90% humidity the heat index would be 98°F. Combined with the psychological effect of expecting it to be cooler at night may account for your experience? (I just plucked those numbers to give an example of the effect I am mention. The change of relative humidity for a 6°F temperature change is probably wrong.)</p>
<p><a href="https://i.sstatic.net/bkLeA.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/bkLeA.png" alt="Heat index chart from weather.gov. Public domain image as it's US Government copyright." /></a></p>

CC BY-SA 4.0
2023-02-03T01:48:00.370Z
Being from Florida, I both agree with the OP that 70s often do feel warmer at night, and with your explanation that moisture probably is a pretty decent part of it.  (I think there may be other reasons for here at least... as when we get 70s in the daytime, it's usually via a cold front, also coming with wind and even drier air)
JeopardyTempest
CC BY-SA 4.0
2023-01-31T14:12:33.737Z
2023-02-01T13:59:03.283Z
2023-02-01T13:59:03.283Z
Mehmet Karatay
<p>During the day, the sunlight is kept out of your house by the roof (assuming you don't have a glass ceiling or windows on your roof). At night, the sun sets and the outside atmosphere is allowed to emit infrared radiation. If there are clouds out, they emit infrared radiation back down to the surface. The atmosphere, itself, also emits radiation back (greenhouse effect), so the surface doesn't get too cold.</p>
<p>Now let's compare what happens at night in your house. Presumably, your roof and house absorbs a lot of radiation during the day. During the night, your house emits radiation, but more than outside, since it is hotter (<a href="https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law" rel="nofollow noreferrer">Stefan-Boltzmann equation</a>). Your roof/ceiling emits radiation both inside and outside the house. This keeps the radiation &quot;trapped&quot; inside the house.</p>

CC BY-SA 4.0
2020-09-10T23:50:48.123Z
2020-09-10T23:50:48.123Z
BarocliniCplusplus
<p>Assuming you are talking about the sensed temperature outdoors...</p>
<p>Solar heating of the surface creates circulations at various scales. One example is a seabreeze, which occurs due to differential heating between land and water and can occur at any scale.</p>
<p>So winds are generally stronger during the day. As the wind blows across your body, heat is removed from you and given to the atmosphere.</p>
<p>Generally stronger winds during the day leads to more heat loss from the body for a given air temperature.</p>

CC BY-SA 4.0
2023-02-03T03:48:31.823Z
Including circulations that mix vertically... mixing down the often greater atmospheric wind speeds aloft.
JeopardyTempest
CC BY-SA 4.0
2023-02-03T02:29:49.060Z
2023-02-03T02:33:43.980Z
2023-02-03T02:33:43.980Z
Moist_occlusion
<h2>Because you are actually hotter.</h2>
<p>Body temperature changes fairly predictably though the day and varies by several degrees.</p>
<p>Your body temperature is highest a few hours before you go to bed (assuming a normal diurnal work schedule). It drops through the night which is why you often feel coldest in the early morning. this pops up a lot in sleep studies since people often feel like they don't need a blanket when they go to sleep and wake up in the early morning desperately wanting one.</p>
<p>If you are a little warm during the day you are going to be very warm later in the day crawling into a well insulated bed reflecting a lot of that heat back, but may well wake up feeling cold.</p>
<p><a href="https://i.sstatic.net/EDKXi.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/EDKXi.png" alt="enter image description here" /></a></p>
<p><a href="https://en.wikipedia.org/wiki/Human_body_temperature" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Human_body_temperature</a></p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678948/" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678948/</a></p>

CC BY-SA 4.0
2023-02-03T01:50:23.133Z
What a great answer.  Silly meteorologist over here never even considered that!
JeopardyTempest
CC BY-SA 4.0
2023-02-02T00:18:29.033Z
2023-02-02T00:23:29.930Z
2023-02-02T00:23:29.930Z
John
<p>Why does the same temperature feel hotter at night? For example, 70 degrees literally feels hot at night when outside but during the day 70 degrees feels just mild when outside. Why is that? And another example is that it feels hotter at night in your house during the summer than during the day and why is that when it is hotter outside during the day and cooler at night but the opposite when inside your house?</p>

CC BY-SA 4.0
2020-09-07T12:11:36.083Z
As a European, 70 degrees always feel *extremely* hot to me... You should at least specify that you are talking about °F, or even better, use the metric system so everyone can understand.
Jean-Marie Prival
CC BY-SA 4.0
2022-08-28T14:42:01.050Z
this sounds like a personal medical question unless you have some studies supporting this being a widespread phenomenon.
John
<temperature><geothermal-heat>
Why does it feel hotter at night?
Ryan Amalfitano
# Why does it feel hotter at night?

(Asked by: username_0 on 2020-09-05)

Why does the same temperature feel hotter at night? For example, 70 degrees literally feels hot at night when outside but during the day 70 degrees feels just mild when outside. Why is that? And another example is that it feels hotter at night in your house during the summer than during the day and why is that when it is hotter outside during the day and cooler at night but the opposite when inside your house?

**Tags:** temperature, geothermal-heat

> **Comments:**
> **username_1**: As a European, 70 degrees always feel *extremely* hot to me... You should at least specify that you are talking about °F, or even better, use the metric system so everyone can understand.  
> **username_2**: this sounds like a personal medical question unless you have some studies supporting this being a widespread phenomenon.  

---

## 5 answers

### Answer by username_3 on 2022-08-25. Score: 3

A physical explanation makes no sense at all as we know the temperature continues to fall. In addition, all the surfaces that emit IR at night also do during the day, as IR radiation is just a function of temperature.

The answer has to be local environmental, biological or psychological.

* **Local environmental** - humidity can rise at night, and air currents fall reducing evaporation and thus raising perceived temperature.
* **Biological** - In a poorly ventilated room, humidity can rise at night and body warmth can also raise the temperature.
* **Psychological** - Your sensitivity to heat may be higher.


---

### Answer by username_4 on 2023-01-31. Score: 3

Could the answer be that the temperature falls at night compared to what it was during the day? It is unlikely to stay the same temperature during the day and night on a regular basis. The drop of temperature would increase the relative humidity, compared to the day, and so it will feel 'muggier' at night, which might lead to you thinking it feels hotter. The vague idea I'm proposing is that the '[heat index](https://www.weather.gov/ama/heatindex)' increases at night or at least stays similar. Your brain may then expect it to feel cooler at night and so notice the heat more.

For example if it's 90°F and 55% humidity then the heat index is 97°F. If at night these readings change to 84°F and 90% humidity the heat index would be 98°F. Combined with the psychological effect of expecting it to be cooler at night may account for your experience? (I just plucked those numbers to give an example of the effect I am mention. The change of relative humidity for a 6°F temperature change is probably wrong.)

[![Heat index chart from weather.gov. Public domain image as it's US Government copyright.](https://i.sstatic.net/bkLeA.png)](https://i.sstatic.net/bkLeA.png)

> **Comments:**
> **username_5**: Being from Florida, I both agree with the OP that 70s often do feel warmer at night, and with your explanation that moisture probably is a pretty decent part of it.  (I think there may be other reasons for here at least... as when we get 70s in the daytime, it's usually via a cold front, also coming with wind and even drier air)  

---

### Answer by username_6 on 2020-09-10. Score: 2

During the day, the sunlight is kept out of your house by the roof (assuming you don't have a glass ceiling or windows on your roof). At night, the sun sets and the outside atmosphere is allowed to emit infrared radiation. If there are clouds out, they emit infrared radiation back down to the surface. The atmosphere, itself, also emits radiation back (greenhouse effect), so the surface doesn't get too cold.

Now let's compare what happens at night in your house. Presumably, your roof and house absorbs a lot of radiation during the day. During the night, your house emits radiation, but more than outside, since it is hotter ([Stefan-Boltzmann equation](https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law)). Your roof/ceiling emits radiation both inside and outside the house. This keeps the radiation "trapped" inside the house.


---

### Answer by username_7 on 2023-02-03. Score: 2

Assuming you are talking about the sensed temperature outdoors...

Solar heating of the surface creates circulations at various scales. One example is a seabreeze, which occurs due to differential heating between land and water and can occur at any scale.

So winds are generally stronger during the day. As the wind blows across your body, heat is removed from you and given to the atmosphere.

Generally stronger winds during the day leads to more heat loss from the body for a given air temperature.

> **Comments:**
> **username_5**: Including circulations that mix vertically... mixing down the often greater atmospheric wind speeds aloft.  

---

### Answer by username_2 on 2023-02-02. Score: 2

## Because you are actually hotter.

Body temperature changes fairly predictably though the day and varies by several degrees.

Your body temperature is highest a few hours before you go to bed (assuming a normal diurnal work schedule). It drops through the night which is why you often feel coldest in the early morning. this pops up a lot in sleep studies since people often feel like they don't need a blanket when they go to sleep and wake up in the early morning desperately wanting one.

If you are a little warm during the day you are going to be very warm later in the day crawling into a well insulated bed reflecting a lot of that heat back, but may well wake up feeling cold.

[![enter image description here](https://i.sstatic.net/EDKXi.png)](https://i.sstatic.net/EDKXi.png)

<https://en.wikipedia.org/wiki/Human_body_temperature>

<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678948/>

> **Comments:**
> **username_5**: What a great answer.  Silly meteorologist over here never even considered that!  

---

