does pool water evaporate in cold weather

Does pool water evaporate in cold weather? Evaporation is a fascinating process that works like magic when it comes to water.

However, most people think it is only a phenomenon they experience in hot climates. Is that really the case?

If that is true, does pool water evaporate faster in cold weather? Well, let’s learn more about it now!

Yes, pool water can evaporate in cold weather, but it is not as fast as in hot weather. 

Understanding the Process of Evaporation

understand the process of evaporation

Water vapor is formed when water undergoes a phase change from a liquid to an invisible gas.

Imagine water magically vanishing into the air – that is what we call evaporation!

Interestingly, water on the ground or pool can transform into vapor and rise into the sky. 

The Magic Behind Evaporation

Evaporation occurs due to the presence of heat energy. Heat provides a force that helps water molecules overcome the bonds that hold them together.

When exposed to heat, water transforms and becomes steam, also known as water vapor. Heat is a factor that aids in the transformation of water into vapor.

Fact: Water is more likely to turn into vapor when it reaches a boiling temperature of around 212°F or 100°C.   

How Temperature Affects Evaporation Rates

temperature affecting evaporation rates

Evaporation occurs in water at room temperature.

It happens even in cold water because, at those temperatures, some water molecules have sufficient energy to separate from the rest of the water molecules and turn into vapor.

When a molecule that is moving faster than the others reaches the surface, it can separate from the other molecules.

Water can evaporate on cold days, but the process works quite slowly. 

Does Pool Water Evaporate in Cold Weather?

Yes, it is possible for pool water to evaporate even in cold weather. When pool water evaporates, it is because the water molecules on the surface of the pool have enough energy to turn into vapor and go into the air. 

How Much Water Will Evaporate from a Pool in the Winter?

will water evaporate in the winter

In the summer, the amount of water you use for your pool depends on things like where you live and how big your pool is.

However, it is possible that you might be losing about 1/4 inch of water each day, or maybe even more.

That is due to evaporation.

How to Confirm Evaporation?

Getting in touch with a builder in your area can help you decide whether you notice evaporation or you have any leaks.

The builder in your area has equipment that can detect leaks and find their origin. They may use a device that you can use to measure how quickly something evaporates.

However, you can easily conduct a simple test yourself to help figure out if a leak or evaporation causes the water loss.

  1. Get a bucket.
  2. Tie it to a step in your swimming pool.
  3. Fill it up with water, ensuring it is at the same level as the water level in your pool.
  4. Leave it in place overnight.
  5. Check the water level the next morning. 

What Does It Mean?

 If the water level in the pool has gone down, but the level in the bucket hasn’t, there’s a good chance there’s a leak.

If the levels drop at the same rate, the cause is likely evaporation. 

Factors Affecting Pool Water Evaporation

factors that affect pool water evaporation

Pool owners and managers need to understand specific factors affecting evaporation in cold weather.

It is important to:

  • Manage water levels.
  • Conserve resources.
  • Keep the pool environment balanced.

Let’s explore the factors that cause pool water to evaporate in cold weather and discuss ways to minimize its impact.

Temperature Differential

The temperature difference between the pool water and the air around it affects how much it evaporates in cold weather.

When the temperature of the air is lower than that of the pool water, the air takes in heat from the surface of the water. This causes the water molecules to become more energetic and turn into vapor.

This phenomenon is especially noticeable in areas with big temperature differences between day and night.

Fact: When there is a greater difference in temperature, the rate of evaporation increases. 

Relative Humidity

relative humidity on evaporation

Relative humidity is important when it comes to the evaporation of pool water.

 When the air is dry, it does not have much moisture and can easily soak up water vapor from the pool’s surface.

When it is cold outside, the air tends to be less humid, so evaporation happens more quickly.

That is why dry air draws moisture from the pool, causing the water to evaporate more quickly. 

Wind Speed

The wind speeds up the evaporation of pool water in certain ways. It takes away the air that is already full of moisture from the surface of the pool and replaces it with drier air.

During cold weather, it is common to experience brisk winds, especially when transitioning between seasons.

When the wind is blowing strongly, it can cause water to evaporate more quickly, even if it is not very warm outside. 

Solar Radiation

solar radiation on evaporation

Even though it may be colder outside, solar radiation can still affect how much water evaporates from a pool.

When sunlight shines on the water, it gives the water molecules the energy they need to escape from the liquid and turn into vapor.

Solar radiation can still cause evaporation even when the weather is cooler.  

Barometric Pressure

barometric pressure on evaporation

The barometric pressure influences the rate of evaporation in a pool. It is essentially the weight of the air pushing down on the pool’s surface.

In cold weather, certain factors have a greater impact on determining evaporation rates, such as:

  • Temperature
  • Humidity
  • Wind

During colder weather, the barometric pressure tends to be higher, meaning the water may still evaporate but won’t happen as quickly. 

Pool Temperature and Water Chemistry

water chemistry and pool temperature

The rate of evaporation is affected by the temperature of the pool water.

When the water is colder, it takes more energy to heat it up to the point where it can evaporate. This can make the process slower.

Fact: Ensure that the water chemistry is balanced; if the chemical levels are off, it can change how the water behaves and how quickly it evaporates. 

Misconceptions about Pool Water Evaporation in Cold Weather

water evaporation in cold weather misconceptions

You may have gathered how evaporation works in cold weather.

But, the truth is that many people still have various misconceptions about pool water evaporating in colder weather.

Here is a bit about the most common misconceptions related to the issue: 

Evaporation Happens only in Warm Weather

Many people mistakenly believe that pool water only evaporates in hot weather, but that is not true.

Of course, evaporation rates are generally higher in hot and dry conditions. However, it’s important to note that evaporation still occurs even when the temperature decreases.

Pool water molecules always have kinetic energy, regardless of the air temperature.

As long as there is a difference in temperature and air movement, evaporation will keep occurring. 

Wind Has No Impact on Evaporation

wind impact on evaporation

When the weather gets cold, it usually comes with chilly winds.

Some people who own pools might think that wind does not have much of an impact on evaporation during these seasons.

Not true!

Regardless of the temperature, wind plays a crucial role in speeding up evaporation. Cold, dry winds can potentially cause higher rates of evaporation compared to warm, calm air.

Fact: The wind blows away the moist air from the pool's surface, which allows drier air to come in and encourages more evaporation. 

Some Mitigation Strategies to Consider

mitigation strategies to consider

If your pool water level drops in winter, it could be due to evaporation.

Here are some mitigation strategies to try:

MethodsWhy Does It Work?
Use pool coversServes as a water-air barrier, and reduces wind, sunshine, and heat loss. 
Windbreaks and landscapingWindbreaks like fences or bushes reduce wind-induced evaporation, and the airflow is slowed by landscaping components, helping in retaining moisture
Humidity controlUsing humidifiers or water features improves humidity surrounding the pool
Fact: In winter, cooling pool water reduces evaporation; in fact, a slight temperature adjustment can preserve water tremendously. 


Does pool water evaporate in cold weather? Contrary to popular belief, evaporation does not happen only in warm weather.

The truth is that evaporation can still take place in cold weather, though the speed is not as noticeable.

Still, it is important to use mitigation strategies to ensure you do not lose your pool water to evaporation.