Pittsburgh Curly

A Curly Girl in da ‘Burgh

It’s not the humidity, it’s the….. humidity

Posted by pittsburghcurly on January 23, 2009

I’ve taken this information and given it its own separate page. My views and opinions on how dew points work continue to evolve, and having all of this on its own page allows me to edit as needed.

Edited on 3/5/09 to revamp the chart for more specific winter temps.

When many curlies talk about their humidity and their hair, they often look at relative humidity. While this makes some sense in a humid summer, it really doesn’t give a clear picture. Once winter hits, it can still be 100% humidity, but your curls will not spring out like they will on a summer day that is 100% humidity.

That is because there is a difference between relative humidity and actual humidity, or how much water really is in the air.

If you want to use humidity to gauge what types of hair products you need, you need to check out your dew point.

Dew point is the temperature at which water will condense and form dew (or fog), hence the name dew point.  The catch is that the dew point cannot be higher than the air temperature. If it’s 20 degrees with 100% humidity, the dew point will be 20 or so. If it’s 90 degrees with high humidity, the dew point will often be in the 70’s.

How much water the air can hold all depends on the air temperature. Think of a cold day as a shot glass. It can only hold a little bit of water. Now, think of a hot day as a keg.  It can hold a lot more water. So, even if your cold day/shot glass is 100% full of water, it still isn’t that much water compared to a 1/4 full keg/hot day.

What most people consider a “humid” day really means a “high dew point day.” Many people start to feel uncomfortable when the dew point reaches 60 degrees, and at 70 degrees, it feels quite oppressive.

What does this mean for you and your hair? Does all of this meteorological mumbo jumbo really mean anything when it comes to how your curls behave? You betcha!

If there isn’t much moisture in the air, there is little for your hair to retain. Like your skin and sinuses, (think of those wintertime frozen boogers!) hair is often drier in the winter. The tight perky curls you had in the summer will often take a looser pattern in the winter. That’s fine, and pretty normal. It’s nothing to panic over. But, if you totally lose your curl pattern and see a bunch of flyaway static-like poofy frizz, there are things you can do.

If appropriate, get a humidifier. I have a plug-in one that I use so my nose isn’t super dry, and it seems to help with my hair too.

Conditioners. You will need richer, thicker conditioners in the winter than you did in the summer. You will probably also have to condition more often. I prefer heavier conditioners with things like shea butter. Look for conditioners made for dry hair, or those that claim to be thick and rich. I’m a big fan of Aubrey Organics Honeysuckle Rose conditioner this time of year. Do be careful not to over-condition, but do condition enough so that your hair isn’t ending up being a static poofball.

Humectants. A boon to curls in the spring and summer, a bane to them in winter. This article by Curl Chemist Tonya McKay will give you a much better explanation of the role of  humectants and humidity than I ever could. The main thing is that you need to avoid humectants in dry weather conditions as much as possible. While someone in Boston may only have to avoid them in the winter, someone in Utah may have to avoid them most of the year.

To quote a part of the article

In extremely low-humidity conditions, such as a cold, dry winter air, there is no appreciable amount of water in the air for the humectant to attract to the surface of the hair. In this particular type of climate, the best one can hope for with most traditional humectants is for them to prevent evaporation of water from the hair into the environment. Also, under these circumstances, there is some risk of the humectant actually removing moisture from the cortex of the hair itself, creating the problem it was intended to prevent.

The main humectants one sees in hair care products are glycerin, honey, propylene glycol, and panthenol/vitamin B5. If you can avoid most of them (which can be difficult) you’ll do a lot to help keep moisture in your hair. The Aubrey conditioner mentioned above is humectant free, as are others. This is one of those annoying ingredient issues that requires lots of label reading time. Hair gels often contain humectants, which is why they work so well in the summer. You can switch to a curl cream if that works better for you, or use your gel over a leave-in conditioner to see if the conditioner will be enough of a buffer between your hair and the hemectants of the gel.

Leave-in conditioner. If you don’t use a leave-in any other time of the year, you way want to consider one in the winter. A leave-in can add an extra layer of protective moisture to your hair. Just look for one without humectants!

If you want an easy way to check you local dew point, plug in you zip code into the Weather Channels search bar on the top of their page.  The results will show you the dew point right below the pressure.

I, along with Boticelli Babe and Colorado Curly, being the hair science geeks that we are, talked about it enough that there is a simple, if theoretical, temperature chart.

  • Dew point bleow 15 – very dry. Use as much moisture and emollients as you hair can handle without overconditioning. Many will have to expect a looser curl pattern at this point. For those who like to occasionally straighten their hair, this is a good time for it since you may have less curl to fight.
  • Dew point 15-30 – Dry, add moisture and emollients. Limit or cut out humectants.
  • Between 30-40 can be iffy. Some people can tolerate more humectants. Other cannot. Very trial and error in this range.
  • Between 40-60. Prime curly range. You should get some curl without that summer frizz. Find a balance between moisture and humectants that works for you.
  • Dew point 60 and up, you’ll need less moisture (usually) and more humectants to help keep the environmental moisture out of your hair, causing that summer frizz. Even those who like moisture will not need as much of the heavy stuff as they did in the winter. This is the time for your hard hold gels. Once the dew point gets past 70, it’s pretty miserable anyway, so you may just feel better putting you hair into an updo. Alas, curly updos will have to wait for another post. 🙂

Weather and how it affects hair can seem like a daunting issue at first. But, with time, experimentation, and patience, you’ll learn exactly what to use on your hair just by looking at the dew point for the day.

Still confused? Just leave a comment, and I’ll be happy to answer.


10 Responses to “It’s not the humidity, it’s the….. humidity”

  1. Marjorie said

    It’s surprising how much hair chemistry reminds me so much of my old chemical engineering classes. I’m glad you broke this down though, making it easier to understand.

  2. Jill said

    Girl, you are saving me some writing time with this post! I’m linking to it tonight on my own blog — thanks for putting this out there. And so concisely, too!

  3. msgiblet said

    Being the “dewpoint checking addict” that I am, I really enjoyed reading this!

  4. curlywurlygurly said

    It’s rather interesting how the environment/ weather effect ones hair… I’d be struggling with my hair and after reading this and other information about dew points it makes sense.

    Only difference for me is that instead of being dry and cold, it’s dry and hot here. I’m gathering the same guide lines apply even though it’s hot not cold?

    thanks 😀

  5. pittsburghcurly said

    curlywurlygurly, your’re right. Low dew points in hot weather can make you your hair dry just like low dew points in cold weather. I just don’t see that where I live! 😀

  6. Katrina said

    Brava! Brava! Keep preachin’ the dew point, sistah! *high five*

  7. […] much of an issue until I really looked at some of my older hair pictures. After reading RCC’s blog post on dew points the lightbulb finally went off. Curlies almost turn into wavies during the winter […]

  8. […] an earlier post, I described how low winter dew points  can affect curl pattern. I then followed it up with pictures to show what I […]

  9. Shones said

    Does the dew point also impact us if we’re in temperature-controlled conditions (indoors) all day?

  10. pittsburghcurly said

    Oddly, yes, it seems to.

    Most of us go from a climate controlled residence to a climate controlled vehicle to a climate controlled workplace. Yet, the outside weather still affects the hair. Even though I work indoors and even exercise indoors in a gym, the humidity level definitely affects my curl pattern and frizz potential. Now, some people do notice an increase of dryness when having to use central heat because central heat tends to make indoor air drier than usual. Regardless, outdoor humidity seems to have a big impact on curly hair whether or not we are actually spending time outdoors or not.

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