Why Is Water Cold?

Water is not cold by nature. It takes on the temperature of its surroundings and can be hot, warm or cold. This post explains why water so often feels cold, why it warms up slowly, and what cold water does to the body.

Why is water cold?

Water is not always cold, but it often feels cold. When water is cooler than your skin, it carries heat away from your body much faster than air does. Water also needs a lot of heat to warm up, so lakes, oceans and tap water can stay cool long after the air has warmed. Evaporation cools water and wet skin even more.

Keep reading for the details.

10 Properties of Water and What They Mean for Temperature

Several physical properties control how water gains, loses and moves heat. Some explain why water feels cold. Others are often mentioned but have little to do with it.

Each one is explained below.

1. Easily Transfers Heat

Liquid water conducts heat roughly 25 times better than air, based on standard conductivity tables, although far worse than metals such as copper. When you touch or stand in water that is cooler than your skin, it pulls heat from your body much faster than air at the same temperature would. This is the main reason water feels colder than air.

When water is exposed to cold temperatures, it loses heat to its surroundings until it reaches the same temperature. This is why the water in colder climates is colder than water in warmer climates.

2. Heating Capacity

The amount of heat energy needed to increase the temperature of water is significant.

According to the USGS, it takes 4,184 joules of heat to raise the temperature of one kilogram of water by 1°C, compared with 385 joules for a kilogram of copper. As a result, water heats up slowly and cools down slowly. A lake or ocean that cooled over winter can stay cold well after the air has warmed up.

3. Latent Heat of Fusion

Melting ice takes a lot of heat: about 334 kilojoules for every kilogram, according to OpenStax College Physics. The ice absorbs that heat from whatever is around it, and its temperature does not rise until it has melted. Freezing is the reverse. Water gives off heat as it turns into ice.

This is why ice keeps a drink cold for a long time: it soaks up heat from the drink as it melts.

4. Vaporization and Condensation

Water has a high latent heat of vaporization: about 2,256 kilojoules for every kilogram. Turning liquid water into vapor takes a lot of heat. When water vapor condenses back into liquid, it gives that heat off again.

Therefore, boiling water requires a lot of heat.

Evaporating water takes this heat from the water left behind and from nearby surfaces such as skin. This is why evaporation has a cooling effect.

5. Cohesive in Nature

The molecules in water are attracted to each other, meaning they stick together.

This is called cohesion.

Cohesion gives water a high surface tension. Surface tension does not stop heat from entering water. Its link to temperature is indirect: because water molecules hold on to each other, water has a low vapor pressure and needs a lot of energy to evaporate.

6. Water Molecules Are Adhesive

The molecules in water are also attracted to other substances (this is called adhesion).

Adhesion explains why water clings to other surfaces. It has no direct effect on how cold water is.

7. Water is Highly Dense

Water is a relatively dense substance.

The density of water is roughly 1 gram per milliliter. Density changes with temperature. The USGS notes that water is densest at about 39°F (4°C) and that denser water sinks below less dense water. This is why the bottom of a deep lake stays cold in summer while the surface warms up.

8. Vapor Pressure

Vapor pressure does not make water cold, but it is linked to evaporation. In a closed container, vapor pressure is the pressure reached when molecules leave the liquid as fast as they return to it.

In other words, it’s the pressure of the water vapor molecules above the liquid.

Vapor pressure rises as water gets warmer, because the molecules have more energy and escape the liquid more easily. Higher vapor pressure is a result of warmer water, not a cause of it.

9. Specific Gravity

Specific gravity is a measure of the density of a substance relative to the density of water.

The specific gravity of water at about 4°C is 1.000, because water is the reference that other substances are compared with. Specific gravity does not explain why water is slow to heat up. That comes from its high specific heat (see number 2).

10. Rate of Evaporation

Evaporation is the process that changes liquid water into water vapor. It needs energy, and the USGS explains that evaporation removes heat from the environment, leading to a net cooling. This is why wet skin feels cold. A breeze makes the effect stronger by helping the water evaporate.

This video by Johnny Harris is about hot and cold water:

Why Is Water Cold in the Shower?

A shower usually runs cold at first because the hot water left sitting in the pipes has cooled down since the last use. That cooled water has to run out before hot water from the heater arrives. The U.S. Department of Energy says insulating hot water pipes reduces heat loss and shortens the wait for hot water.

A shower can also turn cold partway through when a household uses hot water faster than the water heater can supply it. Storage water heaters have a first hour rating, which is the number of gallons of hot water the heater can supply per hour, starting with a full tank.

Finally, even a warm shower can feel chilly when you step out, because water evaporating from wet skin removes heat.

If you turn up the water heater to fix a cold shower, be careful. The U.S. Consumer Product Safety Commission urges people to set water heaters to 120°F to prevent scalds. It says burns occur with a six-second exposure to 140°F water, and that older adults and children under five are most at risk.

Why Is Water Cold in the Summer?

Lakes, rivers and the ocean often feel cold in summer because water warms up much more slowly than air and land.

A hot day does not mean the water is warm. Cold water is dangerous even in summer. The National Weather Service says sudden immersion can trigger gasping and rapid breathing in water as warm as 77°F, and that cold shock from water at 50 to 60°F can be as severe as from water at 35°F. Dress for the water temperature, not the air temperature, and wear a life jacket in and around the water.

The same property works the other way later in the year. Water cools down more slowly than land, so large bodies of water help even out the temperature swings that nearby towns and cities experience.

Evaporation also cools water in summer.

When water evaporates, it takes heat with it, which cools the water that is left behind. This is why sweating cools you down: the sweat takes heat from your skin as it evaporates.

Why Is Tap Water Cold?

Cold tap water gets its temperature mainly from the ground.

Water mains are buried, so the water in them takes on the temperature of the ground at that depth, not the temperature of the air in your home, according to a National Renewable Energy Laboratory paper. Ground temperature changes more slowly than air temperature, so tap water often feels cool in summer, and its temperature rises and falls with the seasons.

Water also feels colder than air at the same temperature, because it carries heat away from your skin much faster than air does.

But once it’s in your glass, it will slowly warm or cool until it reaches the same temperature as the surrounding air.

Why Is Water Cold in an Earthen Pot?

Water stays cool in an unglazed earthen pot because of evaporation. The clay is porous, so a little water works its way into the pores of the pot wall and evaporates from the outside surface. Evaporation removes heat, which cools the water left inside. The effect depends on humidity: it is strongest in dry air and weak in humid air, according to an analysis by the Nimbkar Agricultural Research Institute.

Why Is Deeper Water Colder?

Deeper water is colder than shallower water for a number of reasons.

One explanation has to do with how much sunshine reaches the water. The deeper you go, the less sunlight there is since the sun’s rays can only go so far into the sea.

This indicates that the ocean’s bottom water is significantly colder than its surface water.

The way water circulates is a further explanation. Cold water sinks to the bottom while warm water rises to the surface.

Between the warm surface layer and the cold deep water is a transition layer called the thermocline, where the temperature drops quickly with depth. In the deep ocean, NOAA says the temperature never moves far from about 39°F (4°C). Lakes work the same way in summer, with warm water on top and cold water below.

Are All Oceans Cold?

Oceans are a very important part of Earth’s climate system.

They store a lot of heat and help to regulate the global climate. However, not all oceans are cold. In fact, some parts of the ocean can be quite warm.

The water near the equator is usually warmer than the water at the poles. 

This is because the sun’s rays hit the equator more directly than they hit the poles. The water near the surface of the ocean can also be quite warm in some places.

This is because the sun heats up the ocean’s surface more than the deeper layers of water.

However, there are still cold deep waters even in these warm parts of the ocean. These deep, cold waters are a very important part of the ocean’s climate system.

Because the ocean can store and release large amounts of heat over long periods, it plays a central role in stabilizing Earth’s climate, according to NOAA Climate.gov.

Final Thoughts: Why Is Water Cold?

Water is not cold by nature. It feels cold when it is cooler than your skin because it draws heat from the body much faster than air, and it stays cool because it takes a lot of heat to warm up. Treat cold water with respect: it can be dangerous even on a warm day.

More articles about the cold:

• Is Exercising in Cold Weather Good for You?
• Is Tesla Good for Cold Weather?
• Is Bass Fishing Good in Cold Weather?
• What Is Cold Pressed Juice?
• Why Is My Semen Cold?

Sources

USGS Water Science School (temperature and water)
USGS Water Science School (specific heat capacity)
USGS Water Science School (water density)
USGS Water Science School (vapor pressure)
USGS Water Science School (evaporation)
USGS Water Science School (adhesion and cohesion)
HyperPhysics, Georgia State University (thermal conductivity)
OpenStax College Physics (phase change and latent heat)
National Weather Service (cold water hazards and safety)
Mayo Clinic (hypothermia)
NOAA (thermocline)
NOAA (layers of the ocean)
NOAA Climate.gov (ocean heat content)
National Renewable Energy Laboratory (mains water temperature)
U.S. Department of Energy (insulating hot water pipes)
U.S. Department of Energy (sizing a water heater)
CPSC (avoiding tap water scalds)
Nimbkar Agricultural Research Institute (earthen pot water cooler)
Ohio State University (water temperature)

Reviewed October 2026. We corrected the explanations of why water feels cold, including heat conduction, specific heat, latent heat, vapor pressure, cold showers, tap water, earthen pots and deep water, and added cold water and scald safety guidance, using the USGS Water Science School, NOAA, the National Weather Service, OpenStax, Mayo Clinic, the U.S. Department of Energy and the CPSC.