Hot days and feeling ‘muggy’ could have more to do with the dew point than humidity. Picture John Grainger
Hot days and feeling ‘muggy’ could have more to do with the dew point than humidity. Picture John Grainger

Stop blaming humidity for your frizzy hair

HOT oppressive temperatures on the Northern Rivers in the past few weeks has led to lots of frizzy hair and feeling 'muggy'.

It's not the heat but the humdity to blame, right?

Not according to the Bureau of Meterology. That feeling of mugginess may have more to do with the "dew point" rather than humidity.

Dew point is the temperature air must be cooled in order to produce condensation (dew).

It represents how much moisture is in the air: the higher the dew point temperature, the greater the atmospheric moisture content, according to the BoM.

What's the difference between dew point and humidity?

They both measure moisture in the air, but dew point is related to the quantity of moisture, while relative humidity expresses how close the air is to saturation. Relative humidity is the amount of moisture as a percentage of the amount that air can hold-and warmer air can hold more moisture than cooler air.

Because of its direct relationship to fluctuating temperature, relative humidity doesn't provide suitable guidance on how much moisture is available at a specific location. Dew point however, is relatively consistent.

In warm, sultry weather, moisture in the air can impede your body's ability to cool down.

One of the ways your body cools itself is by the evaporation of moisture from your skin. When the air is moist, this process slows down and you feel hotter for longer. So the higher the dew point, the longer it takes for your body to cool itself.

If you're used to the tropical north, you may find the ranges in this scale low, particularly during spring and summer where dew points are commonly above 24 °C.

On the other hand, if you're from southern Australia, you might find these ranges high.

You can find your 'dew points' in the BoM daily weather observations.