Statistics: Large Data Set (Terms)

What does daily mean temperature mean?

The average of the hourly temperature readings during a 24-hour period

What does daily total rainfall mean?

The total rainfall or solid precipitation such as snow and hail which has melted per day

What does tr or trace record?

Rainfall amounts less than 0.05mm

What is daily total sunshine?

The amount of sunshine per day recorded to the nearest tenth of an hour

What is daily mean wind direction and windspeed?

The daily wind direction and windspeed averaged over 24hrs from midnight to midnight

What is the daily mean windspeed and wind direction measured in?

Knots

What are mean wind directions given as?

Given as bearings and as cardinal (compass) directions

How is the data for mean windspeed categorised?

Categorised according to the Beaufort scale

If the mean windspeed is categorised as 0 on the Beaufort scale, then what is it described as?

Calm

If the mean windspeed is categorised as 1-3 on the Beaufort scale, then what is it described as?

Light

If the mean windspeed is categorised as 4 on the Beaufort scale, then what is it described as?

Moderate

If the mean windspeed is categorised as 5 on the Beaufort scale, then what is it described as?

Fresh

If the mean windspeed is categorised as 0 on the Beaufort scale, then what is the average speed at 10 metres above ground?

Less than 1 knot

If the mean windspeed is categorised as 1-3 on the Beaufort scale, then what is the average speed at 10 metres above ground?

1 to 10 knots

If the mean windspeed is categorised as 4 on the Beaufort scale, then what is the average speed at 10 metres above ground?

11 to 16 knots

If the mean windspeed is categorised as 5 on the Beaufort scale, then what is the average speed at 10 metres above ground?

17 to 21 knots

What is a knot?

A nautical mile per hour

What is 1 knot equal to in mph?

1.15mph

What does the daily maximum gust mean?

The highest instantaneous windspeed recorded from that day

What is also recorded with the daily maximum gust?

The direction from which it was blowing

What is daily maximum gust measured in?

Knots

What is daily maximum relative humidity given as?

Given as a percentage of air saturation with water vapour

What do relative humidities above 95% give rise to?

Misty and foggy conditions

What are the things recorded for oversea locations?

• Daily mean temperature

• Daily total rainfall

• Daily mean pressure

• Daily mean windspeed

What is daily mean cloud cover measured in?

Oktas

What does oktas mean with daily mean cloud coverage?

Eighths of the sky covered by cloud

What does daily mean visibility mean?

The greatest horizontal distance at which an object can be seen in daylight

What is daily mean visibility measured in?

Decametres (Dm)

What is daily mean pressure measured in?

Hectopascals (hPa)