How To Keep Car Windows From Fogging Up In The Rain

It’s pretty normal for car windows to fog up during rainfall. This could be quite frustrating and unnerving and can even lead to a road accident if you continue driving with it. Have you tried wiping the screen with your wiper blades yet?

Did your windscreen fog up during the last rainfall? Damp weather and low temperature are the common cause of moisture build-up on the windscreen and other windows. The fog on the windows will clear off by turning on the air conditioning system.

But what if you don’t have AC? Don’t worry. We’ll explain how to defog the windshield in the rain without AC. You’ll also learn how to keep car windows from fogging up in the rain. But what causes these foggy windows, anyway?

How To Keep Car Windows From Fogging Up In The Rain

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

What Cause Car Windows To Fogging Up In The Rain?

The primary cause of windscreen and other windows fogging is condensation on the inner surface of the windows. The condensation has nothing to do with the outside windows. That is why turning your wiper blades is useless in foggy situations.

Condensation occurs when there’s high humidity inside the car interior, and the fogging on the windows is because the cabin temperature is hotter than the ambient temperature. Your car windows can fog up when parked in the rain.

This is a normal phenomenon. This is just like pouring cold water into a glass cup. The moment you pour cold water into a glass cup, the glass cup will fog up until the water cools to a certain level. The same applies to your car windows. The moisture will clear off once cold air enters inside the car.

Read Also: How to Aim Fog Lights

How Do I Stop My Car Windshields From Fogging Up When It Rains

You can defog car windows with heat. However, it’s ideal for learning how to keep the windshield from fogging without heat if you like driving with AC always.

Since the windshield and windows fog up because the cabin is hotter than the outside temperature, turning on the air conditioner to make the cabin colder than the outside temperature will clear off the fog.

To make it faster, wipe the windows with a clean, dry, and lint-free towel from the inside before turning on the AC. Different cars come with different features. To ease your defogging task, most vehicles have air vents that enable you to blow cold air to the windshield. This will accelerate the defogging process significantly. 

Whether you’re looking for how to defog windshield in summer rain or winter season, this is what you need. But what if the AC can’t defog the windshield? There’s a likelihood the moisture has mixed with oil, forming a stubborn smudge on the windows.

I know what’s going through your mind – where is the oil from. The air freshener or cleaning solutions you used on the dashboard and upholstery can have little oil. These oils can evaporate to the windows when parked or driving under extreme weather conditions.

Dirt particles inside the cabin can also evaporate oil on the windows. If this is the case, rub a soda or alcohol on a clean towel and wipe the windshield before turning on AC.

Read Also: How To Make Car AC Colder – Everything You Need To Know

How To Keep Car Windshields From Fogging Up In The Rain

Now that we have seen why car windows fog up when it rains, let’s see how to prevent the fog in the first place. As the saying goes, prevention is better than cure. Instead of having fogs impair your view while driving, take the necessary steps to prevent the windows from fogging.

The best parameter to minimize fogging is to always keep the windows clean. Oil particles and dirt on the windows accelerate fogging. So, always clean the windows with water and a clean towel to prevent fog.

Cleaning the windows is a regular thing but if you need a long-lasting solution, try anti-fogging products. There are several anti-fog products on the market shelves. But if you don’t want to spend much time looking for the best product, I’d recommend Car Interior Glass Anti-fog.

Follow the instructions on the pack when applying the products.

how to defog Windows in summer rain


Q: How do you defog car windows in the rain outside?

The best approach to defog car windows is to first clean the interior with a lint-free towel. And after that, turn on the AC to match the cabin temperature with the outside temperature. This will offer you more visibility and is one of the best ways to defog car windows.

Q: How do you Defog the windshield in the rain without AC?

The most efficient way to defog windshields in the rain is by switching on the air conditioner. But sometimes, it’s not worth the cold. Fortunately, we have some hacks on how to defog windshields in the rain without AC.

  • Slightly crack the windows. While this may not be ideal in heavy rain, it is okay in drizzling rain.
  • Switch on the defroster to the minimum setting. This method is like switching on the air conditioner. However, it is not as cold as the air conditioner.
  • Switch off the recirculate settings to allow fresh air into the cabin.

Q: Why do my car windows fog up on the inside when it rains?

As reiterated above, car windows fog up due to condensation inside the cabin, which is caused by high humidity. The windows fog because the inside temperature is hotter than the ambient temperature. This is the same when you pour cold water into a glass cup.

Final Words

Car windshield fogging in the rain is a normal phenomenon. This article has explained the causes, preventive measures, and how to keep car windows from fogging up in the rain.

However, keeping the weatherstripping on your doors in good condition is important. Auto manufacturers make the weatherstripping with rubber material, which can deteriorate over time and cause moisture to creep inside the car. Ensure to replace the weatherstripping when they go bad as it can cause windows to leak when raining.

You can also check out why your windshield is fogging up in summer.

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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