what temperature should you not wash your car

What temperature should you not wash your car? No doubt, you want to keep your car in the best condition, but sometimes, it is better to wait and not wash it.

Sometimes, the temperature is too cold or too hot to help you get the best results. You may end up dealing with scratches, streaks, and even erosion.

So, at what temperature should you not wash your car?

You should not wash your car when the temperature is close to 32°F or over 80°F. 

What Temperature Should You Not Wash Your Car?

It is important to understand that washing your car when it is too hot or too cold is not a great idea. 

When Is It Too Cold to Wash Your Car?

car wash in cold weather

Experts recommend avoiding washing the car when temperatures are low but how low is low?

Below 34oF or 1.11oC is not recommended.

This is just a touch above the point at which water freezes and it may still do so when it lands on the cold metal.

Using warm water or washing the car in the garage can help prevent the water from freezing onto the metal.

The advice is to stick to washing the car when temperatures exceed 49oF (just under 10oC) to avoid freezing the door hinges and locks.

The ideal temperature is between 50oF and 89oF (10oC and 31.6oC). 

TemperatureCar Wash
Below 34FNo recommended
Above 120FNot recommended
Between 50F and 89FIdeal

Issues Associated with Washing Your Car at Low Temperatures

issues of car washing in cold temperatures

It is important to avoid washing your car when the temperature outside is a bit too low, and that is for many different reasons.

For instance: 

Risk of Water Freezing on the Car Surface

Winter can be harsh on cars. Not only is there more rain and mud around but there is also road salt and other de-icing chemicals that are also causes of corrosion.

Rust causes around $3 million worth of damage each year but during winter, regular washing can limit its impact.

That is true especially if close attention is paid to cleaning the undercarriage, wheels and fenders and bumpers.

Although it can be cold, if it is below freezing, snowing or sleeting, then washing the car is not advised. 

An Important Consideration
car washing below zero

Washing below zero or even slightly above can create ice crystals as the cold metal and cold water meet.

These act like grit and strip the car’s wax finish leaving micro-scratches on the surface of the paintwork.

Fact: Provided temperatures are above zero there is no reason not to wash the car and there is no right or wrong way to do it, even in winter. 
Potential Damage to Car Components 
potential damage to car components

Sometimes, it is difficult to avoid washing the car even on very cold days.

In fact, expert advice says to wash cars more regularly during winter, preferably in the afternoon when it is warmer.

They stress the importance of drying the car thoroughly afterwards. However, not on very cold days when thermometers hover around zero.

There is always a risk of ice stripping away the wax protection exposing and dulling the paintwork.

And there is also a risk of scratching the lenses which reduces a light’s effectiveness and visibility on the road.

When it is too cold the water will freeze inside the door frame sealing the door tightly shut and forcing it open will damage both the door, its seal and the door handles.

Fact: Car locks and washer spray outlets are extremely vulnerable to freezing and difficult to defrost so it’s better to avoid getting water in them in the first place. 
Consideration of Local Climate and Freezing Tendencies
consideration of local climate and freezing tendencies

It is not enough to trust the weather forecast, particularly if you live in micro-climate. 

It is the local weather conditions that will dictate the best time to give your car a wash. 

Winter temperatures are highly variable and at some locations, such as in valleys or at altitudes, the temperatures will fall lower than suggested by a general regional forecast.

They also rise and fall throughout the day but wherever you are,  winter conditions can change in an instant.

If you wash your car too late in the afternoon, and do not dry it thoroughly, night-time temperatures will freeze any water left behind. 

When Is It Too Hot to Wash Your Car?

car wash in hot weather

Any type of washing makes use of chemical reactions and these reactions are temperature dependent.

Cleaning agents are developed to work within optimal temperature ranges and work less effectively at the extremes.

There may be times when the ambient temperature is out of the recommended temperature range.

For example, cleaning agents designed to remove dirt, soil and oil work better at 120oF  (48.8oC  ) than 160oF ( 71oC )

Fact: If you live where it is hot and have no choice but to wash the car, the trick is to do it quickly, panel by panel beginning with the roof. 

Issues Associated with Washing Your Car at High Temperatures

There are many reasons why you should not wash your car when it is too hot outside, and that is for various reasons.

For instance:

Rapid Evaporation of Water and Cleaning Agents
rapid evaporation of water and cleaning agents

It is traditional to see queues at the car washes on bright sunny days. However, just as some days are too cold to wash the car, some are too hot.

It is difficult to get the shine you are after. This is because in the high ambient temperature and direct sunlight any water evaporates quickly.

Evaporation happens even faster when the water lands on a hot surface, such as a car. 

Even plain tap water leaves spots, and so will water with cleaning agents added. 

They are formed as the water transforms into a vapor and leaves behind the chemicals within it that as a vapor it cannot support. 

Increased Chances of Water Spots and Streaks

Water spots, smears and streaks are devilishly difficult to shift, especially if they have been left to dry on your car.

Rubbing at them does not make them disappear, they have been baked on.

As they adhere to the car’s surface, the chemicals react with the chemicals in the paintwork to dull your finish.

increased chances of water spots and streaks

Eventually, paint flakes away and offers corrosion a route to bare metal. The hotter it is, the faster evaporation happens.

Adding soap or other cleaning agents won’t slow it. They just add to the cocktail of chemicals left in the residue. 

Recommended Temperature Range to Avoid Washing Car in Hot Weather  

Apart from washing the car being a good way to cool down, sometimes not washing it is not an option, in which case, you should consider when and where.

To a point, the higher the temperature, the easier the cleaning.

car wash temperature range in hot weather

The detergents work better and deal with grease and oil more effectively. Any soil deposits are more soluble.

However, temperatures over 140oF (60oC) will cause the chemicals in the water to fall out as residue.

Consider moving the car under shade so you are both away from direct sunlight or washing it down in the morning or evening when it is cooler.

Fact: The surface of a car left to dry in the sun can reach as much as 200oF, and that can leave spots and streaks if you wash your car. 

Factors to Consider Beyond Temperature

factors to consider beyond temperature

It is important to consider the impact of temperature, but you should pay attention to other factors when washing your car.

For instance: 

Humidity Levels

Humidity, the amount of moisture in the air, can also impact the quality of the wash.

Humidity levels rise and fall through the day, and areas near water are typically more humid.

When the air already has a lot of water in it, such as on a damp, cloudy day, it is difficult to handle things.

It takes more time for water droplets to evaporate from the car’s surface and you have to work harder to dry it.

Fact: In hot humid conditions, paint damage happens faster and is exacerbated by the chemical residues left behind as a result of poor drying. 

Exposure to Sunlight

exposure to sunlight

Prolonged exposure to UV rays in direct sunlight is bad for any kind of paintwork.

On cars, they cause flaking and fading. Some colors fade faster than others. If you live somewhere hot, it is always better to park and wash the car in the shade.

It saves the car’s interior, particularly the dashboard and any leather.

On the exterior, anything plastic is especially vulnerable.

Prolonged direct sunlight makes plastic brittle although regular washing and waxing will make a difference.

The UV rays are refracted by wax and do not make it through applied layers to where they can damage the paintwork.

Takeaway

What temperature should you not wash your car?  Knowing the best way to wash your automobile will help it last longer and protect it from harm.

Car washing is generally safe at any temperature over freezing, but you should avoid doing it when it is extremely cold or hot outside. 

If you want to wash your automobile in comfort and safety, keep the temperature between 50 and 80 degrees Fahrenheit.

By keeping the weather in mind, you can keep your car looking great and avoid any problems during the washing process.