Weather and Waves data

The weather data is provided by UK Met Office and is © Crown copyright 2024, the Met Office and © British Crown copyright 2024, the Met Office

The Wave / Swell height, direction and period data is provided by Open-Meteo,  © 2022-2024 Copyright Open-Meteo.com

Visibility

Visibility measures the distance at which an object can be clearly seen.

 

  • VP (Very Poor)      Less than 1 km
  • P (Poor)                   1.1 km to 4 km
  • M (Moderate)        4.1 km to 10 km
  • G (Good)                10.1 km to 20 km
  • VG (Very Good)   20.1 km to 40 km
  • E (Excellent)           Greater than 40 km

UV

UV exposure index and the protection required to help keep you safe:


0          No risk of UV – It’s safe to stay outside.

1-2       Low – You can safely stay out side. Consider sunscreen in direct sunlight.

3-5       Moderate – Take care during midday hours and do not spend too much time in the sun unprotected. Sunscreen advised.

6-7       High – Seek shade during midday hours, cover up and wear sunscreen.

8-10    Very high – Spend time in the shade between 11am and 3pm. Shirt, sunscreen and hat are essential.

11        Extreme – Avoid being outside during midday hours. Shirt, sunscreen and hat essential.

Beaufort Wind Scale

Force Wind Speed       Wave Height  Description         Sea State

           (mph)               (meters)

0           0-1                   0                    Calm                         Sea like a mirror.

1           1-3                   0-0.3            Light Air                 Ripples with the appearance of scales are formed, but without foam crests.

2           4-7                   0.3-0.6            Light Breeze         Small wavelets, still short, but more pronounced. 

                                                                                                                Crests have a glassy appearance and do not break.

3          8-12                   0.6-1.2             Gentle Breeze         Large wavelets. Crests begin to break. 

                                                                                                                Foam of glassy appearance. Perhaps scattered white horses.

4         13-18                   1-2             Moderate Breeze Small waves, becoming larger; fairly frequent white horses.

5         19-24                   2-3             Fresh Breeze         Moderate waves, taking a more pronounced long form; many white horses are formed.

6         25-31                   3-4             Strong Breeze         Large waves begin to form; the white foam crests are more extensive everywhere.

7         32-38                   4-5.5             Near Gale          Sea heaps up and white foam from breaking waves begins to be blown in streaks 

                                                                                                                along the direction of the wind.

8         39-46                  5.5-7.5             Gale                         Moderately high waves of greater length; edges of crests begin to break into spindrift. 

                                                                                                                The foam is blown in well-marked streaks along the direction of the wind.

9         47-54                  7-10             Severe Gale         High waves. Dense streaks of foam along the direction of the wind. 

                                                                                                                Crests of waves begin to topple, tumble and roll over. Spray may affect visibility

10         55-63                  9-12.5              Storm                 Very high waves with long overhanging crests. 

                                                                                                                The resulting foam, in great patches, is blown in dense white streaks along the direction 

                                                                                                                 of the wind. On the whole the surface of the sea takes on a white appearance. 

                                                                                                                 The tumbling of the sea becomes heavy and shock-like. Visibility affected.

11         64-72                  11.5-16      Violent Storm  Exceptionally high waves (small and medium-size ships might be for a time lost to view                                                                                                                         behind the waves). 

                                                                                                                 The sea is completely covered with long white patches of foam lying along the direction 

                                                                                                                 of the wind. Everywhere the edges of the wave crests are blown into froth. 

                                                                                                                 Visibility affected.

12         72-83                   >14              Hurricane          The air is filled with foam and spray. 

                                                                                                                  Sea completely white with driving spray,

                                                                                                                  Visibility very seriously affected.


Barometric pressure

The standard barometric pressure at sea level is 1013 millibars and a normal range is between 965 and 1040.

High pressure typically indicates good weather, clear skies with the sun warming us and the earths surface.

Low pressure means colder weather, clouds blocking the sun, rain and wind.  Very low pressure over open water creates heavy winds which can turn into hurricanes or  typhoons.

 

Lower barometer means higher sea levels and higher values lower sea levels, roughly 1 millibar is equivalent to 1cm change in the sea level hieght.

Typically this is + / – 30cm, but with extreme pressure / weather changes this can be 60cm or more.

 

Wave data

Height of waves

Waves vary in height, a measurement referred to as ‘significant wave height’ is used, this is the average of the highest third of the waves.  The average most frequent waves will be about half the height of the significant wave and about 15% of waves will be biggger than the significant wave, with maximum wave occuring 1.5 to 2x the significant wave. 
 
Height range
The approximate range is the low and high end of the expected wave range rounded to a whole number (this is due to space available in the bevel).
 
Period of waves offshore 
The wave period is the number of seconds between one wave and the next, but as waves vary in frequency they are measured as the time between significant waves crest to crest.
 
Direction of waves
The arrow shows the average direction on the waves.
If the arrow points towards the coast the waves forecast should be more accurate, if the arrow is parrellel or away from the coast the waves will be smaller.

For a more information see the following links

Met Office – What does this forecast mean

Met Office – Understanding beach forecasts

Thewaveshack –  How to read a surf report