Why is my car’s Windshield Fogged up in Summer?

Windows fogging up in summer seems to be a normal occurrence. Foggy windshields can make driving frustrating both in winter and summer. To make things worse, the blur vision caused by fogging can almost always result in an accident

The steam effect on the windshield can be prevented once you know what to do. So, if you’re asking, “Why is my car’s windshield fogged up in summer?” The reason is not far-fetched.

Also for those asking, “Why is my windshield fogging up on the outside?” Take a moment to read this article to find out the cause of your foggy windshield and what to do about it.

why is my windshield fogging up on the outside

Why is my car’s windshield fogged up in summer?

Foggy windshields are a result of air with different temperatures meeting on the windshield. That should answer your query “Why do car windows fog up in summer?” To be precise, windshield fogging up in the summer is due to hot air outside in the environment hitting the cool windshield.

On the contrary, windshield fogging up in winter is a result of the warm air within a car coming in contact with the cold windshield. In both scenarios, air with different temperatures from outside and inside the car jointly creates the steam on the windshield.

The consequence of a fogged windshield can range from minimal to intense blur vision from inside and outside the car. Driving with a foggy windscreen is not ideal in any case, whether winter or summer. The tendency for an auto crash is relatively high under such conditions.

Read Also: Squeaky Windshield Wipers: Causes and Fixes

How to prevent my windshield from fogging up in the summer

Windshield fogging up in summer or winter is natural. By the way, the steam on the windscreen is a product of a natural occurrence.

However, while you can’t stop nature from creating various occurrences, you can prevent your windshield from fogging up. The preventive measures are very easy to implement. The most effective of the measures include:

Cracking down your windows

During summer, rolling down your car’s windows can help prevent the windshield from fogging up. If you park in a safe area, simply crack down the windows a little bit (about half an inch) to allow fresh air from outside into the car.

This will help prevent the windshields from steaming up. However, do not roll down your windshield if you are not sure of the safety around where you park. Some dubious fellows won’t miss an opportunity to force your windows down to gain unauthorized access to your car.

Clean the windshield with shaving cream

Using shaving cream is another way to prevent your car’s windshield from fogging up. In order to do this, kindly get a nice shaving cream that easily foams when you press it out of the bottle.

Put some of the creams on a soft piece of cloth (cotton) and use it to apply the cream to the windshield. After that, use a dry, neat rag to clean it off the windshield. The cream will create a barrier against steam on the windshields eventually.

Apply potato starch to the windshield

Potato contains sugars and starch that can serve as a repellant against fog build-up on your windshield. So, get a ball of potato; cut it into two halves, and rub the content on your car’s windshield. After that, get a clean piece of soft rag and wipe off the juice from the windshield.

Ensure to wipe off the potato juice from the windshield immediately before it dries up and leaves some whitish stuff on the surface.

Read Also: Silicone Wiper Blades vs. Rubber: What are The Best?

How do you fix a foggy windshield in the summer?

Always remember that “prevention is better than cure.” However, if you failed to implement the preventive measures above, the following recommendations can help if you’re contemplating how to get rid of a foggy windshield in summer.

Engage the windshield wipers

Usually, fog will form on your car’s windshield outside during summer. If this occurs, simply turn the windshield wipers on and regulate them to wipe across the windshield slowly to clear off the fog thoroughly. This is simply how to remove fog from outside windshields.

The wipers are also useful when driving in the rain. Ensure to keep the components working at all times. Try to test them once in a while to ascertain whether they are intact.

Turn down the air conditioning system

Don’t forget that steam build-up can result from hot air meeting your car’s cool windshield, which is caused by the air conditioner. So, you may have to turn down the air conditioning system a little bit to match the temperature out there.

Roll down your car’s windows

Again, this does not only work for preventing the windshield from fogging up. It also helps to clear off fog build-up during summer. Note that windows fog up when AC is on during summer. That is why driving with the windows down is advisable at times.

So, if your car’s windshield suddenly gets steamed up, simply roll down the window and allow the warm air from outside into the car. In a moment, the warm air will clear the fog out of the windshield.

Engage your HVAC system’s fresh air setting

Most modern cars are designed with a heating, ventilation, and air conditioning system (HVAC), which allows a recirculation or fresh air mode.

Engaging the fresh air mode will open a unique air duct in the vehicle’s front area and allow a direct inflow of fresh air instead of the normal air conditioning cooling air. This can also wipe out a seriously fogged windshield.

car windows fogging up inside when parked

Read Also: How to Defrost Windshield Without Heat?


Q: How do you defog your windshield in hot weather?

If your car’s windshield is currently fogged, ensure to implement this quick fix remedy; simply crack the windows open and allow the inflow of fresh air to naturally defog the car’s windshield. However, you may not be able to do this when it’s raining.

So, you may want to firstly turn on the heater in your HVAC system and increase it to maximum (defroster). The hot air from the HVAC system’s vents will simply heat and vaporize the moisture on the windshield. However, you’ve got to bear the heat for a moment while in the vehicle.

After that, turn on the cooling air conditioning and regulate it gradually to the level of normal air outside so that the air within and outside is at a similar temperature level. This will clear off the fog.

Q: Do you use hot or cold air to defog windows?

Hot air is best to help defog your vehicle’s windshield. Naturally, cold air or low temperature easily collects moisture to form fog on windshields. So, reversing the temperature is the best way to defog the windows.

However, the defroster can be pretty hot if you have to stay in the car to defog the windshield. In that case, you will have to endure the heat in the meantime. The process will not take the whole day. So, you can simply wait patiently to do it once and for all.

Q: How do you stop condensation on the inside of car windows?

Vehicle windshield fogging up inside when you park is common in winter. Blasting hot air from your car’s heater will help stop the condensation on the inside of the window. If your car’s windows are condensed or fogged up, simply regulate the HVAC system and turn on the heater.

The warm air from the system will heat up the windows and clear off the water vapor in a moment. Meanwhile, ensure to turn the heater directly towards the fogged windows. This will enable you to achieve the maximum results within a short time.

Q: Why is my car always full of condensation?

If you’re asking, “Why is my windshield fogging up in the winter?” The difference in temperature levels on either side of the car’s windshield is usually responsible for the condensation on the windows. When the warm air inside a car comes in contact with the cold windshield, the combination forms condensation in a moment.

Usually, condensation forms on a car’s windshield when it’s raining. This is because of the high humidity within the car. When fog forms on your windshield, it will suddenly blur your vision, thereby making driving difficult.

This is one of the common reasons why accidents happen on rainy days. Understanding how to defog car windows in the rain without AC will help you overcome this challenge.

Q: Why is my windscreen always steamed up?

Your car’s windscreen will always steam up when there is warm moisturized air contacting the cold windscreen. For instance, your body temperature and breath are enough to warm up the air and increase the amount of moisture within your car.

When this occurs, especially with a colder temperature outside, it will steam up the windscreen. A classic example is when you leave your car outside overnight. The heat within will automatically fog up the windshields before daybreak.

Getting into the car and zooming off like that can be disastrous in the long run. That’s why you need to clean your car thoroughly in the morning before setting out.

Q: How do you dehumidify a windshield?

One of the simplest ways to dehumidify a windshield is to engage the heater in the car. Hot air holds moisture and causes the humidity level in a place to drop gradually.

When you blast warm air from your car’s heater on a steamed windshield, it will defog the windshield in a moment. Therefore, you must ensure that your car’s HVAC system is working perfectly to enable you to handle issues like this easily.

Meanwhile, ensure to find out how to defog a car’s windshield or windscreen in summer humidity because the approach is different from what you do in winter.

Q: Where is the best place to put a dehumidifier in a car?

The dashboard is the best place to put a dehumidifier in a car. If you have a non-electric dehumidifier, placing it close to your car’s windscreen in the dashboard area will enable it to extract moisture from the windscreen.

On the other hand, if you have an electric dehumidifier, you can place it in the same position or somewhere hidden within the car.

Some of the best brands of dehumidifiers you can use in your car include Eva-Dry Wireless Mini Dehumidifier, Pingi LV-A300 Dehumidifier, and Patu Renewable Wireless Dehumidifier, Gurin DHMD Renewable Wireless Dehumidifier, etc.

Final Words

Although nature’s course cannot be altered, it is possible to take precautions to minimize or correct the adverse effects. So, if you were wondering, “Why is my car’s windshield fogged up in summer?” The effect is a result of nature’s operation.

Therefore, since warm air from outside can form steam on a cool windshield, implementing measures to keep the temperature inside and outside a car at the same level will help you handle this situation.

So, ensure to follow the recommendations above to prevent your windshield from fogging up or remedy an already steamed windshield.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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