|Christchurch Weather Digest|
The "Feels Like" temperature depends on the actual outside air temperature, but also takes into account relative humidity and the strength of the wind to assess how our body actually feels.
If the outside temperature is less than 10ºC we calculate "Wind Chill", but if the outside temperature is greater than 14ºC we calculate an "Apparent Temperature". (There is a rollover between Wind Chill and Apparent Temperature).
In winter a strong wind can feel much colder than the measured temperature. Conversely on a humid day in summer it can feel uncomfortably hotter than the temperature suggests.
On windy days the speed of moisture evaporation from our skin increases and serves to move heat away from our body making it feel colder than it actually is.
At higher temperatures humidity plays a greater role. When we perspire, the water in our sweat evaporates. This results in the cooling of our body as heat is carried away from it. When humidity is high, the rate of evaporation and cooling is reduced, resulting in it feeling hotter than it actually is.
The Dew Point temperature combines both air temperature and relative humidity into a single number expressed in degrees.
It's the temperature to which 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.
The dew point directly affects how "comfortable" it will feel outside.
The Cloud Base is the lowest altitude of the visible portion of a cloud.
Clouds are formed when water vapor condenses. This happens when the air temperature is equal to the dew point.
The difference between the temperature and the dew point is known as the "spread".
The cloud base is calculated by dividing the spread by 2.5, then multiplying by 1000 and adding in the height above sea level.
Where we live the altitude above sea level is 6 metres or 19.7 feet.
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