|Christchurch Weather Digest|
To estimate the “Feels like” temperature, in colder weather “wind-chill” is calculated to account for the coolness of the wind as it removes heat from us.
In warmer weather an “apparent temperature” is calculated accounting for the sultriness we feel when our perspiration is unable to cool us down efficiently on a warm muggy day.
There is a roll-over between 10ºC and 14ºC from the wind chill formula to the apparent temperature.
The calculations take into account air temperature, wind speed, and humidity.
- NZ MetService
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.
In Christchurch the altitude above sea level is 20 metres (66 feet).
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