Human hair is extremely sensitive to humidity—so much that some hygrometers (devices that indicate humidity) use a hair as the measuring mechanism, because it changes in length based on the amount of moisture in the air. Straight hair goes wavy. If you have curly hair, humidity turns it frizzy or even curlier.
Humidity! It's common for hair to curl up tighter when it is more humid. If your hair is on the borderline between straight and wavy, humidity can make it wavy, while on days where the air is more dry, it will act straighter.
What to use: Since Loose curls tend to be fine, a little external boost from humidity can be of benefit to help define its curls. Too much humidity, however, can cause all hair types to frizz, but especially loose curl types.
This Is Why Humidity Makes Your Hair Curly
Water molecules want to create balance, so they'll move from the oversaturated air into your dry hair. Once the water molecules are inside of your hair, they reshape the hydrogen bonds holding your hair together. As a result, your hair gets frizzy, and in some cases, curly.
Your wet hair naturally forms into waves and ringlets.
Look down at your hair, and see if it's curling into waves and ringlets. If it is, you're probably a curly girl. Water resets your hair to its natural state. If it's curly, you'll be able to tell!
If your hair curls without your doing much to it, it's likely that your hair texture is curly. If your hair tends to fall flat without some scrunching or product, then your hair texture might be wavy. Curly and wavy hair needs a bit more hydration and moisture to help you avoid dry hair or frizzy hair.
Curly hair strands cluster together and wind around themselves in a spiral or looser curl shape. This texture needs plenty of moisture to encourage a defined pattern, but a little frizz can give it personality. Wavy hair is when strands curve or form an "S" shape. Straight is when strands go straight up and down.
Hair and humidity are definitely not friends — arch enemies are more like it. If the hair cuticle is open the moisture from humidity can penetrate the hair shaft causing frizz and flyaways. With all the moisture in the air penetrating the hair and weighing it down, it's no wonder our curls go flat in record time.
Humidity causes straight hair to become wavy. Wavy hair becomes curly, and curly hair forms even tighter curls. All types of hair are subject to frizz-causing humidity. However, certain types of hair, such as dry, damaged, or over-processed hair, are more susceptible.
Colder is better for curls as dew points between 40-60° F (4-15°C) are considered optimal. If the dew points are too high, it will cause curly hair to absorb moisture from the air and result in frizz.
In high humidity, around 90% or so, curls tend to frizz and lose their shape quickly. McKay says, “In high-humidity conditions, this can cause curly hair to swell so much that cuticles are raised, making the surface of the hair very rough.
How summer humidity can aid with natural hair growth. It's hair growing season. The warmer the climate, the better it is for your hair. Increased humidity can provide your hair with a sort of green house effect environment.
The humidity delivers what no product or machine can do. Those tiny water molecules plump my curls, and give it levity and weightless bounce.
Hair Texture
If it dries straight without a bend or curl, then you have straight hair (or type 1 hair as it is commonly referred to). If it dries with a slight curve or “S” shape, then it's considered wavy hair (type 2).
Genetics, hormones, and the environment can all play a role in the change in your hair texture. The most common reason for your hair changing in texture is hormones. Hormones can cause your hair to become wavy, or can even explain why your naturally curly hair has gone straight.
The molecules in your hair are held together by strong chemical bonds, some of which are sensitive to water and can temporarily change their shape. The shape of your hair reflects the shape of the molecules of which it is made.
“Any type of moisture in the air or your body temperature will cause your hair to revert back to its natural texture.” This means heat, rain, humidity, sweat, and even stress are not your friends when your hair is straight.
It's very normal to have a mix of curl patterns on the same head of hair. It starts with your genetics. You see, the gene for curly hair is not completely dominant. It can remain dormant until activated and then it changes the shape of the hair follicle which changes the hair that grows from it.
Air Drying Curly Hair
No heat: Overdoing the heat (whether it's from a flat iron or hairdryer) can deprive your hair of moisture, and affect the health of your curls. Air drying is ideal for healthy curls since it saves them from heat damage and dry/split ends.
“It can be tricky! But the best way to tell is by looking at the shape of your hair closer to the scalp. Hair that is wavy tends to have S-shaped strands, either tight or loose, and usually lays closer to the head. Curly hair has more corkscrew pattern and the curls have more 'lift' from the scalp.
The texture of a person's hair is determined by the shape of their hair follicles. Your follicle shape is partly determined by what genes you have. Your DNA might cause you to have perfectly round follicles.
Puberty, menopause and pregnancy all cause hormonal shifts that can make your tresses go from straight to curly hair. In fact, 40-50% of women experience major changes in their hair while pregnant or breastfeeding.