So why does it feel colder when it’s humid?

So why does it feel colder when it's humid?  Temperatures are dropping, but the humidity is still higher. You may think that is not true, but listen here. One hundred percent humidity – it's raining. Anyone who has ever been caught in a cold rain wearing inadequate clothing knows that 100% humidity during cool weather makes you feel much colder than if it were dry at the same temperature. This strongly suggests that high humidity (dampness) makes you feel colder.

But how can that be when high humidity on a hot day just makes you feel hotter. Sweating is our body's cooling mechanism. When the humidity is low, sweat evaporates easily and therefore cools our body. On a hot, humid day, sweat does not evaporate as easily, so the body's cooling mechanism does not work as well. When it's cool and humid, the body does not need a cooling mechanism, so the body sweats less. The high humidity does not limit evaporation to keep the body warm as it does on a hot humid day.

On a cold rainy day the falling rain soaks our clothing to make us feel colder. On a cool damp day, it's less obvious, but our clothing can still absorb some moisture from either the damp air or our bodies. Whether it is raining or simply damp, wet clothing does not keep us as warm as dry clothing. Our clothing keeps us warm on cool days by trappin air between our bodies and our clothing. The clothing with the layer of trapped air prevents our bodies from losing heat by convection currents, which transfer heat by circulating air like a cool breeze on a hot day.

On a very cool damp day, however, this layer of trapped air contains water molecules. If it is damp, our clothing is also likely to contain some water molecules. It takes more heat to warm water than air. If the layer of air next to the skin is damp, it takes more body heat energy to warm it. Another effect contributing to the cooler feeling outside on a damp day is the lack of sunlight. A damp day is more likely to be overcast and have less radiant solar heating. 

So why does it feel colder when it's humid – humidity makes us hotter in the summer and colder in the winter. Call us at LHT Cooling, Heating & Refrigeration, Inc., to assess your dehumidification system!