Large Data Set

Question 1

Variables included in the: large dataset.

Answer 1

• Daily Maximum Temperature
• Daily Total Rainfall
• Daily Total Sunshine
• Daily Maximum Relative Humidity
• Daily Mean Windspeed
• Daily Maximum Gust
• Daily Mean Wind Direction
• Daily Maximum Gust Direction
• Cloud cover
• Visibility
• Pressure

Question 2

Daily Maximum Temperature

Answer 2

• Values for the daily maximum temperature are given in Degrees Celsius and to one decimal place.
• A negative value indicates a reading below 0^ C.
• If a reading is not available, it is listed as ‘n/a’.

Question 3

Daily Total Rainfall

Answer 3

All the totals given are in millimetres (mm).
* If the total amount of rainfall collected is less than 0.05 mm, it is referred to as a trace of rain.
* These values are indicated by ‘tr’ in the data set.
* If a reading is not available, it is listed as ‘n/a’.

Question 4

Daily Total Sunshine

Answer 4

Values for this are given in hours and to one decimal place.
For example, an entry of ‘4.4 hrs’ indicates that there were 4.4 hours of sunshine in that location on that particular day.
If a reading is not available, it is listed as ‘n/a’.

Question 5

Daily Maximum Relative Humidity

Answer 5

Relative humidity is a measure of how close the air is to being saturated with water vapour.
Values for this are recorded as percentages (%). Relative humidities above 95% are associated with mist and fog.
If a reading is not available, it is listed as ‘n/a’.

Question 6

Daily Mean Windspeed

Answer 6

The daily mean windspeed is given in knots.
1 knot is 1.15 mph. If a reading is not available, it is listed as ‘n/a’.
The windspeeds are also categorised according to the Beaufort scale.
This is an empirical and discrete scale.
You can read a little about the Beaufort scale online.

Question 7

Daily Maximum Gust

Answer 7

The maximum gust speed is the maximum instantaneous speed that occurred over a 24 hour period.
It is calculated as an average over a 24 hour period. If a reading is not available, it is listed as ‘n/a’.

Question 8

Cloud cover

Answer 8

This is a discrete variable in the data set. It is measurement of the fraction of the celestial dome covered by cloud.
It is measured in eighths. The technical unit used in this case is called oktas.
0 oktas indicates a completely clear sky, while 8 oktas indicates complete overcast.

Question 9

Visibility

Answer 9

Visibility is measured horizontally. Readings are given in metres. A dash indicates unavailable data.