How Cold Is Too Cold to Go Outside With Wet Hair?

Let's settle this once and for all.

The Myth: You'll Catch a Cold

First, let's address what everyone's mom said: going outside with wet hair will make you sick.

That's not how colds work. Colds are caused by viruses, not cold temperatures. You can't catch a cold just from being cold or having wet hair in the cold.

But there's a grain of truth in it. When you're cold, your body diverts resources to keeping you warm. This can temporarily weaken your immune system, making you slightly more susceptible to getting sick if you're exposed to a virus.

The real risk isn't the cold itself. It's that you're more likely to be indoors with other people during winter, where viruses spread easily. Being cold and run-down might make it easier for a virus to take hold if you're exposed to one.

So no, wet hair in cold weather won't directly give you a cold. But being freezing cold all the time because you keep going out with wet hair might make you more vulnerable to getting sick when you are exposed to germs.

Your mom wasn't completely wrong. She just had the mechanism backwards.

What Happens to Wet Hair in Extreme Cold

Forget about getting sick for a minute. Let's talk about what literally happens to your wet hair when you walk outside in Toronto winter.

It freezes. Like, actually freezes solid. When it's cold enough, the water in your hair turns to ice. You'll have crunchy, frozen hair within minutes.

Your hair can break. Frozen hair is brittle. If you run your hands through it or take your hat on and off, you can literally snap frozen hairs. This causes breakage and damage.

Your scalp gets painfully cold. Wet hair pulls heat away from your head way faster than dry hair. Your scalp will be freezing, which is not only uncomfortable but can give you a headache.

Frostbite is theoretically possible. In extreme cold (we're talking -30 or colder), wet skin can develop frostbite faster than dry skin. Your scalp is skin. If it's wet and exposed to severe cold for too long, frostbite is a risk.

The freeze-thaw cycle damages your hair. Going from frozen outside to warm inside repeatedly stresses your hair. The expansion and contraction can damage the hair shaft over time.

You'll be miserable. Even if nothing medically bad happens, being that cold sucks. Your whole walk or commute will be uncomfortable.

So while you might not get sick, going out with wet hair in serious cold is still a bad idea for other reasons.

The Temperature Threshold

So what's the actual answer? How cold is too cold?

Above 0°C: You're probably fine. Your hair might feel cold and damp, but it's not going to freeze. You'll be uncomfortable but not damaged.

0°C to -10°C: Not ideal but manageable. Your hair might start to freeze in spots, especially if it's really wet. Wear a hat and you'll survive, but your hair won't love it.

-10°C to -20°C: This is where it gets problematic. Your hair will freeze. You'll be really cold. If you must go out, your hair should be mostly dry and you absolutely need a hat.

Below -20°C: Just don't. Seriously. Blow-dry your hair or wait. Going out with wet hair in extreme cold is asking for frozen, broken hair and a miserable time.

Wind chill matters too. -10°C with no wind is different from -10°C with strong wind. Wind chill makes everything worse. If the "feels like" temperature is below -15°C, treat it like it's colder than the actual temperature.

The simple rule: If it's cold enough that you need a winter coat and gloves, your hair should be dry before you go outside.

What About Hats?

Guys think throwing on a toque solves the wet hair problem. It helps, but it's not a perfect solution.

A hat keeps your head warmer. It traps some heat and prevents your wet hair from being directly exposed to freezing air. This is better than nothing.

But your hair still freezes underneath. The hat doesn't stop water from turning to ice. It just slows it down and keeps the frozen hair contained.

Wet hair plus hat equals weird hair later. When your hair freezes against your head under a hat, it dries in whatever flattened, weird shape the hat forced it into. You'll have serious hat hair all day.

Hats can trap moisture. If your hat isn't breathable, moisture gets trapped between your wet hair and the hat. This can actually make the problem worse.

Taking your hat off indoors is awkward. Your hair is going to look terrible. Frozen, then thawed, then flattened. You'll want to keep your hat on all day, which looks weird in meetings.

A hat is better than no hat if you absolutely must go out with wet hair. But it's not a good solution. It's damage control at best.

The Hair Damage Factor

Even if you don't care about being cold or looking weird, repeated exposure to extreme cold with wet hair damages your hair over time.

The cuticle gets roughed up. Freezing and thawing repeatedly makes the outer layer of your hair shaft rough and damaged. This leads to frizz, dryness, and breakage.

Your hair becomes more brittle. Damaged hair breaks more easily. You'll notice more short broken hairs and split ends.

Color fades faster if you dye your hair. The freeze-thaw cycle can strip color from dyed hair faster than normal.

Your hair loses moisture. Ironically, even though your hair is wet when you go outside, the freezing process actually dehydrates it. Dry winter air makes this worse.

Styling becomes harder. Damaged hair doesn't hold styles well. It's harder to work with and looks rougher even when you style it properly.

If you do this regularly all winter, by March your hair will be a mess. One time probably won't wreck everything, but making it a habit will.

The Blow Dryer Is Your Friend

I know most guys hate blow-drying their hair. It feels like extra effort you don't have time for. But in Toronto winter, it's not optional.

It takes three minutes. Literally. You don't need to style it perfectly. Just get it mostly dry. That's enough to prevent freezing.

You don't need it completely bone dry. Slightly damp is fine. You just need the bulk of the water out so it won't freeze solid.

Use medium heat, not high. High heat can damage your hair too. Medium heat is plenty and works fast enough.

Blow-dry in the direction you want your hair to go. Even quick blow-drying can set your hair in the right direction if you pay attention to how you're doing it.

Keep a small travel dryer at work. If you shower at the gym before work or need to wash your hair mid-day, having a dryer available solves the problem.

Three minutes of blow-drying is way better than 20 minutes of being freezing cold on your way to work and then dealing with damaged, weird-looking hair all day.

What If You're Already Outside With Wet Hair?

Okay, you messed up. You're already outside and your hair is freezing. Now what?

Put a hat on immediately. Even if your hair is already frozen, a hat will slow down further heat loss and make you less miserable.

Don't touch your hair. Frozen hair breaks easily. Resist the urge to run your fingers through it or mess with it.

Get inside as fast as you can. The longer you're exposed, the worse it gets. Don't make extra stops.

When you get inside, let it thaw gradually. Don't blast it with hot air or rub it vigorously. Let it warm up naturally for a few minutes.

Once it's thawed, fix it gently. Use your fingers to rearrange it. Don't pull or yank on it.

Apply some leave-in conditioner or oil if you have it. This helps protect the hair that just went through freeze-thaw stress.

It's not ideal, but you can minimize damage if you handle it right once you realize your mistake.

The Morning Routine Solution

The real answer is building a routine that prevents this situation in the first place.

Shower at night instead of morning. Your hair has all night to air dry. Problem solved.

If you must shower in the morning, wake up 10 minutes earlier. Give yourself time to blow-dry properly instead of rushing.

Keep your bathroom warm. A warm bathroom helps your hair dry faster even without a blow dryer.

Use a microfiber towel. They absorb way more water than regular towels. Gets your hair closer to dry with less effort.

Plan your showers around your schedule. If you know you're leaving in five minutes, that's not the time to wash your hair.

Keep dry shampoo handy. If your hair isn't actually dirty, just use dry shampoo instead of washing it. Saves time and avoids the wet hair problem entirely.

A little planning prevents you from being the guy with frozen hair on the subway.

The Bottom Line

How cold is too cold to go outside with wet hair? If it's below freezing and you need a winter coat, your hair should be dry.

You won't die. You probably won't even get sick. But you will be uncomfortable, your hair will look terrible, and repeated exposure will damage your hair over time.

Just blow-dry it. It takes three minutes and saves you from a lot of misery. Or shower at night and let it dry while you sleep. Or use dry shampoo instead of washing it in the morning.

Toronto winters are long and cold enough without making yourself more miserable by going out with wet hair. Take the three minutes to dry it properly.

Need a haircut that's easier to maintain during Toronto winter? Book with Jded and we'll set you up with something that works with your routine.