<p>The subsurface temperature will vary due to the soil type: sand, clay, loam, silt and the degree of saturation of the soil, soil thickness, the thermal conductivity of the soil, the surface temperature (time of the year) and the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil-temperature" rel="nofollow noreferrer">albedo of the surface</a>.</p>

<p>Temperature changes within soil become less variable with depth.</p>

<p>So far I have only found information for two regions: the <a href="https://builditsolar.com/Projects/Cooling/EarthTemperatures.htm" rel="nofollow noreferrer">US-Virgina</a> and <a href="https://www.researchgate.net/publication/30500372_Measurements_of_Ground_Temperature_at_Various_Depths" rel="nofollow noreferrer">Cyprus</a>. Following is a series of curves for the US. A similar diagram is available for Cyprus, but its locked in a pdf file.</p>

<p>In Cyprus, the soil temperature at 3 m depth varies between 18 °C and 20 °C. In the US, at a depth of 12 feet (3.6 m) the temperature varies between 60 °F and 65 °F (15.5 °C and 18.3 °C).</p>

<p>These results are similar, but it needs to be noted both locations are in temperate climate zones. The latitudinal extent of Virginia is between 36.5° and 39.5° North and Cyprus is 35° North.</p>

<p><a href="https://i.sstatic.net/UMeiM.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/UMeiM.gif" alt="enter image description here"></a></p>

<p>From research undertaken in <a href="https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/11046.pdf" rel="nofollow noreferrer">Australia</a>, the temperature at depth in a soil is also dependent on the air temperature and hence the latitude. At a depth of 1 m the soil temperature is 35 °C at latitude 10° South and 12 °C at latitude 45° South. There will be a corresponding difference at 5 to 10 m depth.</p>

<p><a href="https://i.sstatic.net/Spq5D.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Spq5D.png" alt="enter image description here"></a></p>

<p>The <a href="https://www.bgs.ac.uk/reference/gshp/gshp_report.html" rel="nofollow noreferrer">British Geological Survey</a> states:</p>

<blockquote>
  <p>About half of the solar radiation received by the Earth is absorbed at the surface. As a result, the ground temperature shows seasonal fluctuations to depths of about 15 m where the temperature is approximately equal to the mean annual air temperature(8 - 11° C in the UK). Below this the ground temperature increases at, on average, 2.6 °C per 100 m due to heat flowing from the interior of the Earth. Mean temperatures at 100 m depth in the UK vary between about 7 - 15°C.</p>
</blockquote>

CC BY-SA 4.0
2019-12-20T05:52:02.430Z
2019-12-20T19:27:02.353Z
2019-12-20T19:27:02.353Z
Fred
<p>In the US, when constructing a geothermal heat pump, common knowledge holds that anywhere in the country the subsurface ground temperature at a depth of 5 m will be around 10 to 15 C, which is a good temperature to provide cooling in summer and heating in winter.</p>

<p>I was trying to find information on subsurface temperatures at various depths around the world -- I had assumed that this value would be fairly consistent, but I am unable to confirm.</p>

<p><strong>How does subsurface temperature vary around the world (say at a depth of 5 to 10 m), and what does this depend on?</strong> I am not concerned about the effect of local phenomenon such as volcanic activity.</p>

<p>I'd be particularly interested in a map (static or interactive) presenting this information.</p>

<temperature><geothermal-heat>
How does the subsurface earth temperature vary around the world?
LShaver
# How does the subsurface earth temperature vary around the world?

(Asked by: username_0 on 2019-12-20)

In the US, when constructing a geothermal heat pump, common knowledge holds that anywhere in the country the subsurface ground temperature at a depth of 5 m will be around 10 to 15 C, which is a good temperature to provide cooling in summer and heating in winter.

I was trying to find information on subsurface temperatures at various depths around the world -- I had assumed that this value would be fairly consistent, but I am unable to confirm.

**How does subsurface temperature vary around the world (say at a depth of 5 to 10 m), and what does this depend on?** I am not concerned about the effect of local phenomenon such as volcanic activity.

I'd be particularly interested in a map (static or interactive) presenting this information.

**Tags:** temperature, geothermal-heat


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## 1 answers

### Answer by username_1 on 2019-12-20. Score: 5

The subsurface temperature will vary due to the soil type: sand, clay, loam, silt and the degree of saturation of the soil, soil thickness, the thermal conductivity of the soil, the surface temperature (time of the year) and the [albedo of the surface](https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil-temperature).

Temperature changes within soil become less variable with depth.

So far I have only found information for two regions: the [US-Virgina](https://builditsolar.com/Projects/Cooling/EarthTemperatures.htm) and [Cyprus](https://www.researchgate.net/publication/30500372_Measurements_of_Ground_Temperature_at_Various_Depths). Following is a series of curves for the US. A similar diagram is available for Cyprus, but its locked in a pdf file.

In Cyprus, the soil temperature at 3 m depth varies between 18 °C and 20 °C. In the US, at a depth of 12 feet (3.6 m) the temperature varies between 60 °F and 65 °F (15.5 °C and 18.3 °C).

These results are similar, but it needs to be noted both locations are in temperate climate zones. The latitudinal extent of Virginia is between 36.5° and 39.5° North and Cyprus is 35° North.

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

From research undertaken in [Australia](https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/11046.pdf), the temperature at depth in a soil is also dependent on the air temperature and hence the latitude. At a depth of 1 m the soil temperature is 35 °C at latitude 10° South and 12 °C at latitude 45° South. There will be a corresponding difference at 5 to 10 m depth.

[![enter image description here](https://i.sstatic.net/Spq5D.png)](https://i.sstatic.net/Spq5D.png)

The [British Geological Survey](https://www.bgs.ac.uk/reference/gshp/gshp_report.html) states:

> About half of the solar radiation received by the Earth is absorbed at the surface. As a result, the ground temperature shows seasonal fluctuations to depths of about 15 m where the temperature is approximately equal to the mean annual air temperature(8 - 11° C in the UK). Below this the ground temperature increases at, on average, 2.6 °C per 100 m due to heat flowing from the interior of the Earth. Mean temperatures at 100 m depth in the UK vary between about 7 - 15°C.


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