large data set

months for recording data

may to october

weather stations for reording in uk

Camborne, heathrow, hurn, leeming, leuchars

overseas stations

beijing, jacksonville, perth

daily mean temp

recorded by thermometers

values are in degrees and tenths(degrees celsius)

average of the hourly temp readings

daily total rainfall

commencing at 0900 greenwich time

tr - trace amount less than 0.05 mm

all totals are in mm

daily total sunshine

measure by an instrument that measures the amount of solar radiation exceeding a threshold

recorded in hours and tenths

daily maximum relative humidity

measure of how close the air is to being saturated with water vapour

above 95% is listed as mist and fog

daily mean windspeed

given in knots = 1.15mph

averaged over the 24 hoursd

daily maximum gust

maximum instantaneous speed that occured during the 24 hours

daily mean wind direction

averaged over the 24 hours and rounded to the nearest 10 degrees

daily maximum gust direction

the direction is where the wind was blowing when the maximum gust during the hour commencing at the time fo entry occured

measured in degrees from true north

cloud cover

measured in eighths (Oktas)

the fraction of the celstial dome covered by cloud

visibility

the greatest distance a object can be seen and recognized at a daylight level

measured using visiometer

visibility is measured horizontally

values are noted in decameters

dash indicates data not available

pressure

the mean sea level pressure has been calculated from a measurement made from station level

measured in hectopascal