Large Data Set

Large Data Set (Weather) — Revision Notes

Overview of the Large Data Set

  • Months included: May to October

  • Years included: 1987 and 2015

  • Months with 30 days: June and September

  • Time period for measurements: 24 hours (0900–0900)

Locations Included

UK Cities

  • Camborne

  • Heathrow

  • Hurn

  • Leeming

  • Leuchars

Worldwide Cities

  • China: Beijing

  • Australia: Perth

  • USA: Jacksonville

Temperature Data

  • Daily mean temperature:

    • Units: Degrees Celsius (°C)

    • Accuracy: to the nearest 0.1°C

  • Temperature range at Heathrow: 8°C – 28.7°C

  • Coldest UK location:

    • Leuchars (12.2°C)

  • Warmest UK location:

    • Heathrow

  • Warmest UK months:

    • July (Camborne, Heathrow, Hurn)

    • August (Leeming, Leuchars)

  • Warmest location worldwide:

    • Jacksonville (24.8°C)

  • Coldest location outside the UK:

    • Perth (15.2°C)

  • Range of temperatures:

    • UK: 3.8°C

    • Worldwide: 28.7°C

  • Change from 1987 to 2015:

    • Temperatures have increased at all locations

Rainfall Data

  • Units: millimetres (mm)

  • Accuracy: to the nearest 0.1 mm

  • tr: trace rainfall (less than 0.05 mm)

  • n/a: not available

Maximum Rainfall

  • UK: Heathrow — 51.6 mm (26/08/2015)

  • Worldwide: Perth — 102 mm (17/05/2015)

Wettest and Driest Cities

  • Wettest UK city: Camborne (2.8)

  • Wettest worldwide: Jacksonville (5.9)

  • Driest UK city: Heathrow (1.8)

  • Driest worldwide (excluding UK): Beijing (2.1)

Rainfall Patterns

  • UK:

    • Similar patterns with peaks at similar times

  • Worldwide:

    • Peaks occur at varied times

Rainfall Changes

  • Increase in rainfall: Camborne, Hurn

  • Decrease in rainfall: Heathrow, Leuchars, Leeming

Sunshine

  • Units: Hours

  • Accuracy: Recorded to the nearest 0.1 hour

  • Maximum sunshine (Heathrow): 15 hours

  • Minimum sunshine (Heathrow): 0 hours

Humidity

  • Daily maximum relative humidity:

    • Percentage of air saturated with water vapour

  • Relative humidity > 95%:

    • Indicates misty or foggy conditions

Wind

  • Daily mean wind direction & speed: Beaufort Scale

  • Daily maximum gust: Knots

UK Wind Extremes

  • Maximum wind:

    • Leuchars — 23 knots (06/06/2015)

  • Minimum wind:

    • Hurn — 2 knots (03/10/2015)

Worldwide Wind Extremes

  • Maximum wind: Perth — 14 knots

  • Minimum wind: Jacksonville — 0.9 knots

Windiest Months Worldwide

  • May for all cities except:

    • Perth — September

    • Jacksonville — October

Wind Units and Conversions

  • kn (knot): nautical mile per hour

  • 1 knot = 1.15 mph

Beaufort Scale

  • 0: Calm (>1 knot)

  • 1–3: Light (1–10 knots)

  • 4: Moderate (11–16 knots)

  • 5: Fresh (17–21 knots)

  • Daily maximum gust:

    • Measures the highest instantaneous wind speed recorded

Visibility

  • Definition:

    • The greatest horizontal distance an object can be seen in daylight

  • Units:

    • Decametres (Dm), where 1 Dm = 10 m

Pressure

  • Units: hectopascals (hPa)

  • Heathrow 2015 pressure:

    • Maximum: 1036 hPa

    • Minimum: 989 hPa

Cloud Cover

  • Total cloud:

    • How many eighths of the sky are covered

  • Units: Okta