Girls’ Guide to Surf Science

Words by Jessica Eveleigh

Photo by Nathan Smith

Weather, eh? There’s no controlling it. Sod’s law says the surf will be like a millpond when you’ve spent months planning that trip to the coast, or the wind will be a mere whisper for that long-lusted after windsurf trip.

Well, you may not be able to control it, but brushing up on your watersports science will mean you can at least plan around it and will greatly enhance your experience in the ocean.

‘From huge onshore storm waves to beautiful glassy peelers, waves are beautiful,’ says Dr Paul Russell, reader in coastal dynamics at the University of Plymouth. ‘The more you watch them, the more you’ll understand.’ Whether you’re taking the plunge every day at your closest break or exploring new territory, there are two main ways to check conditions. The first is to tap into technology, using online webcams and surf forecasts; the second is to follow the weather yourself. Best is a combination of both.

But before you start, there are a few things you need to know…

A Wave Is Born

Your ride begins as the story of a wave ends. You can feel its power and harness its energy, but where did it come from?

‘Waves are born when the wind ‘rubs’ on the surface of the ocean, imparting its energy from the air to the water,’ says Professor Tony Butt, co-author of Surf Science: An Introduction to Waves for Surfing (Alison Hodge, £18.50). ‘As the water surface becomes rough, the air is able to ‘grip’ better, allowing the waves to grow more quickly.’


No, we’re not talking about that sinking feeling when you realise that it isn’t happening for you because the surf is too small, too big, too messy. A depression is a meteorological term that helps us predict surf.

The tempestuous winds in the Atlantic are down to changes in air flow. The sun heats up the earth’s surface causing warm air to rise and the pressure to drop. As this happens, cooler air from areas of higher pressure whooshes in to fill the gap. This movement is wind. Got that? Good. It’s about to get more complex.

Since the world is not static and is spinning on an axis, the air movement is affected by what’s known as the Coriolis force. In the Northern Hemisphere, the air circulates anti-clockwise; in the Southern Hemisphere, clockwise. Remember the plug hole experiment at school? It’s the same thing.

When a mass of cold air meets a mass of warm air, a depression (or region of low pressure) starts to form. This generates a lot of wind and often a storm. You can see depressions, or lows, forming on a weather chart.

Look at the isobars (the thin squiggly lines with numbers indicating pressure) beginning to circulate around a central depression. Another larger number over this area tells you the pressure. The isobars also more or less mark air movement, when they’re closer together the waves are likely to be bigger and stronger.

Ideally, what you want is closely packed isobars around a depression in the mid-900s some way out in the Atlantic that’s generating sizeable waves heading in your direction.

Swell Time

When the waves leave the stormy centre, they become ‘free-travelling’ and result in swell. The air has ceased its shimmy with the water surface and the swell propagates of its own accord towards the coast.

As it does so, the waves become more organised. This is when we watch and wait for corduroy lines on the horizon and pumping surf. Start waxing your board.

Local Knowledge

Before you get too excited, though, study local conditions. Each break has its own behaviour and responds differently to chart predictions.

‘You need to know which direction a particular break faces, so that you can tell which swells and winds will hit it,’ says Ben Freeston from Magic Seaweed. ‘You also need to know which tides it works on. This is pretty much a trial and error process for the uninitiated. Keep a note of the forecasts on the good days and compare them to the current ones. You’ll improve with practice.’ And, of course, you can always ask the locals.

You also need to pay attention to the wind as it buffets the coast. A light wind over Europe is sweet. With wind direction, the general rule is that an off-shore wind (good) lifts the waves, giving them better shape and producing cleaner surf. An on-shore wind (bad) does the opposite.

For a beginner who’s happy practising pop-ups in the white water, a cross-shore wind (OK) may not mean perfect peaks, but it’s better than nothing.

Finally, know your body. Stay fit and healthy. You need to be ready when the waves come. And, whatever the weather, the most important thing is to have fun.

Surf for Surf

When the beach is out of striking distance, use the internet to see what’s up with the surf. Bookmark these websites and you will have a complete quiver of forecast tools at your fingertips.

  • A1 Surf:
  • Buoyweather:
  • National Data Buoy Center:
  • Magic Seaweed:
  • The Met Office:
  • Storm Surf:
  • Swell Forecast:
  • World Weather Information Service:

Ideal conditions for…


According to Richard Gowers of the British Kitesurfing Association, you should be rooting for medium strength, cross-shore winds. And, what about the waves? ‘If your level is up to it, then big waves are a good thing,’ says Gowers.


‘It’s safest if the wind is cross on-shore,’ says Andy Holmes of Wet and Windy Watersports. ‘You can’t windsurf directly into the wind, so you don’t want it to be dead on-shore. Too off-shore is dangerous; you might get stranded at sea. Coming in at about 45 degrees with a medium to strong wind strengths is ideal.’


The calmer the better. That means no wind, no swell. ‘It’s easiest and fastest when it’s flat,’ says Holmes.


‘Picture the Maldives,’ says Trev Maynard, diving instructor at Andark Diving. ‘Glorious, flat, calm seas with warm water. To see the big fish, such as sharks, head for where the current breaks on a headlands or reef.’


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