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Why Does My Rain Jacket Get Wet Inside?

A wide arm pose of a women wearing a red rain jacket on a lake background.

Like most people, I try to avoid going out on rainy days. However, one day while hiking, I was caught off guard by a heavy downpour. Fortunately, I had packed a rain jacket.

But while walking back to my camp tent, I noticed that I was feeling some wetness inside a jacket that I assumed to be waterproof. I’m sure most people have found themselves in this situation and wondered why their rain jackets would get wet inside. The main reason for this is perspiration and condensation.

Condensation happens when water vapor comes across a colder surface, hence changing from gaseous to liquid form. Humid air contains a lot of water vapor. And when the external surface of the rain jacket is colder than the interior, water vapor condenses inside, hence making your jacket get wet inside.

Perspiration will also produce water vapor which condenses in the same process. However, you can reduce the amount of sweating by reducing the clothing layer you have worn under the rain jacket. You can also try to generate less body heat by slowing your pace.

For instance, since I am a mountain climber, I like giving my hiking activities ample time. This ensures that I move at a slow pace, hence reducing the amount of sweating. At the end of the day, there is less risk of me soaking up my rain jacket.

How Do I Stop My Waterproof Rain Jacket From Sweating?

A side view of a woman running in heavy rain.

I have learned that the most effective way to ensure my rain jacket does not sweat much is by getting one with pit zips. A rain jacket is like a thermal envelope that traps body heat, hence keeping you warm. A rain jacket with pit zips allows you to open them, thus shedding some of that heat.

This also ensures you perspire less. You do not have to worry about the rain getting inside the jacket because your arms will be covering the pit zips the whole time. While this method is not perfect, it will help reduce the amount of condensation that causes your clothes to get wet.

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Another way to vent off the excess heat from your body is by wearing a separate jacket hood rather than the rain jacket’s hood. As blood flows close to the skin around your neck, it will be cooled by the cool air, reducing body heat. And if you have no issues with getting your wrists and hands wet, then roll the sleeves of the jacket.

A lot of blood flowing near your hand’s surface will be cooled, reducing perspiration. If your rain jacket does not have pit zips, there is no other practical way to decrease the amount of heat trapped inside your jacket without shedding clothing or stopping. Unfortunately, these are not practical solutions when it is raining.

Why Do Rain Jackets Wet Out

For anyone who has ever gone hiking while it is raining, this has probably happened to you. Wetting out is when you are soaked all over despite wearing a waterproof jacket. Unfortunately, on a chilly day, you are at the risk of hypothermia if you do not dry up fast enough.

Most rain jackets are made up of three layers, with the external layer containing a Durable Water Repellent (DWR) finish to repel rain. Ideally, your waterproof jacket should hold off light rain. Wetting out occurs when the rain is heavy and the air surrounding you can no longer contain additional moisture.

When the DWR on your jacket starts wearing off, and you are under heavy rainfall, the moisture buildup inside the jacket will have nowhere to go, hence leaving you all soggy.

How Can I Prevent Wetting Out

While you cannot control the weather, if you like hiking, do not let the rain stop you. Here is what you can do before and during your hike to reduce wetting out.

Before

  • Wash your gear: Ignore the myth that washing your waterproof jacket will prevent it from keeping the rain out. I have washed mine several times, and it is still effective. When dirt builds up on your waterproof rain jacket, it prevents the DWR from being effective. Washing it restores its function.
  • Rewater proof your gear: While most people are not aware, you can waterproof your jacket once the DWR starts wearing off.
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During The Hike

If  you are caught off guard on your trail while it is raining, here are some measures you can take.

  • Unzip: If your jacket has venting zips, unzip them. This will allow any trapped moisture to escape, preventing you from soaking up.
  • Opt for synthetic over down material: It is better to wear synthetic instead of a down jacket for your middle layer. While the down is warmer, it does not do a good job of insulating when wet. Synthetic jackets are always better for rainy days.
  • Pack extra layers: I always pack extra layers when I go hiking, even if it does not look like it will rain. This is for emergencies, as you never know what will happen. Always pack some mid layers because if the rain is relentless and you soak all over, you will have extra clothing to keep you warm.

Does Washing A Waterproof Rain Jacket Ruin It?

While washing a waterproof rain jacket will not ruin it, washing it in ordinary fabric softener and ordinary detergents can harm it. The chemicals in these products easily break down the waterproofing coating, and with each wash, your jacket becomes ineffective.

Fortunately, there are cleaners specifically designed for such outerwear that will keep your jacket clean.

Female in the shop want to buying a fabric softener in a bottle.

How Do You Waterproof A Rain Jacket?

One day I was caught in a rainstorm with only my rain jacket to help me keep dry. Unfortunately, the jacket that I was relying on to keep me warm failed, and I ended up all soaked. When that happened, I knew it was time to waterproof my rain jacket.

The durable water-repellant (DWR) finish ensures your rain jacket is breathable, but waterproof is susceptible to wear with time. Fortunately, you can use a waterproof spray like Granger’s Performance Repel Plus or wash it in a waterproofing agent to restore the effectiveness of your rain jacket. But how do you waterproof your rain jacket?

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Young man with water repellant.

First, wash the jacket and ensure it is clean before spraying it with a waterproofing spray. Put it in the dryer, and when you take it out, it will be repelling water again. You can confirm this by sprinkling some water on your jacket.

If it bead ups, you are good to go. On the other hand, if your rain jacket has something like a hole from one of your hiking adventures, there is no waterproof spray that will prevent it from soaking up. It is time to upgrade to a new rain jacket.

How Often Should I Reproof My Rain Jacket

Besides feeling unpleasant on your skin, a rain jacket whose DWR coating is not functioning properly will lead to condensation inside the jacket. Once you notice that your jacket has become saggy, clingy, and water sinks inside the outer fabric, it is time to reproof with a DWR coating. The frequency of reproofing your rain jacket depends on how often you wear it and the extent to which it is exposed to the elements.

Because I enjoy hiking, I’m always out exploring in different conditions. As such, I reproof my jacket every 3 to 4 months. However, if you do not wear your rain jacket as much and in less extreme weather, you may have to reproof it every 6 to 8 months.

How To Make A Rain Jacket Last Longer?

Besides reproofing your rain jacket, you can make it last longer by reducing abrasion. If you hike with a backpack like most of us, the most common areas exposed to abrasion include the back, under shoulder straps, ends of the sleeves, and under the hip belt. Reducing the amount of time your rain jacket is exposed to abrasion by wearing an insulated hoodie or a wind shirt will make your rain jacket last longer.

The bottom line is that there is no foolproof way to ensure that your rain jacket will not get wet inside. However, it all boils down to you caring for your jacket properly and ensuring that it remains effective for as long as it can.