Times of the Islands Fall 2019

Humidity is a function of the air temperature and the
dew point. “Relative humidity” is basically how close the
air is to 100% saturation. When we have 100% saturation
of the air, the temperature and dew point are the same.
Any time the dew point is less than the temperature, you
will see relative humidity values be lower as well.
Confused yet? Let’s talk a bit more about this dew
point temperature. The dew point relates to how much
water vapor is actually in the air. Water vapor is the gaseous
form of water. As the dew point rises, so does the
amount of water vapor in the air. As dew points decrease,
the amount of water vapor in the air also decreases.
To understand this from a comfort perspective, we
can look at this function in different climates. In the
Islands, wind flow is always from the water, which transports
moisture over the Islands, contributing to higher
dew point temperatures. Contrast the Caribbean climate
against the climate of western New Mexico and other high
desert areas.
In Caribbean climates, it is routine to see dew point
temperatures of 74º to 82ºF, while air temperatures
hover around 88ºF. As mentioned earlier, travelers will
note upon arrival to TCI that the air feels sultry, and to a
degree, wet. Doing activities outside in a Caribbean climate
has a marked effect on the body as well. As you
begin to sweat, the ability of your body to cool itself
is degraded. In order for you to perspire properly and
maintain comfort, it is imperative that your body is able
to get rid of heat via perspiration effectively. When the
air is already highly saturated, your body struggles to
This lizard has the right idea for keeping cool.
evaporate and add your perspiration to the already moist
environment.
This chart pairs dew point temperatures with comfort level. In Caribbean climates, it is routine to see
dew point temperatures between 74º and 82ºF.
Contrast that with western New Mexico where the
air temperature may be 93ºF and the dew point might
be closer to 30º or 35ºF. Here, the air is very dry with
lower amounts of water vapor. Just stepping outside in
temperatures in the low 90s
is usually still surprisingly
comfortable. Start hiking and
biking, doing any outdoor
activity in this environment,
and again your body will start
to perspire to cool itself down.
But there is a big difference.
Remember that the lower the
dew point, the less water vapor
there is in the air. As a result,
the relatively dry air can efficiently
evaporate sweat from
your body. As this occurs, it
is cooling your body by absorbing
the heat via the process of
evaporation. Therefore, when
comparing climates, there are
drastic differences in what the
MARTA MORTON—WWW.HARBOURCLUBVILLAS.COM
18 www.timespub.tc