The science of waves: understanding weather conditions for better surfing

1. Introduction

Surfing is more than just gliding; it's a sport deeply connected to the natural elements. Each session depends on a multitude of meteorological factors that directly influence the size, shape and power of the waves. Yet for many surfers, beginners and experienced alike, these conditions can seem complex and difficult to predict. Understanding the science behind wave formation and how weather forecasts work is essential to maximizing your chances of finding perfect waves while surfing safely.

In this article, we'll break down the main weather elements that affect wave quality and show you how to read and interpret forecasts effectively. Whether you're a surfer looking to improve your skills or a beginner curious about when and where to go surfing, this guide will provide you with the keys to a better understanding of the relationship between the natural elements and surfing.

By learning to decipher the weather forecast, you'll not only be able to choose the best time to hit the water, but also avoid unpleasant surprises such as an unfavorable wind or a messy swell. Better still, you'll learn to anticipate the ideal conditions for your style of surfing and the type of board you're using. So join us on this exploration of the science of waves, and get ready to improve your surfing sessions by accurately choosing the perfect time and place to ride the waves!

2. Weather factors influencing waves

The waves that break on our beaches don't just happen. They are the result of complex meteorological phenomena that sometimes occur thousands of miles from the spot where you're surfing. To better understand what makes the difference between an epic session and a disappointing day, it's essential to understand the main meteorological factors that influence wave formation and quality: wind, swell, tides and currents.

2.1. Wind: a key player in wave formation

Wind is a fundamental element in the creation of waves. As it blows across the surface of the ocean, it transfers its energy to the water, generating waves that propagate over long distances. However, not all winds are equal in terms of surfing quality. There are two main types of wind that influence wave shape:

• Onshore wind: This is a wind that blows from the sea towards the land. Although it can create waves, it tends to make them messy and less well-shaped. Onshore wind often creates turbulent conditions, which can make waves harder to surf. Surfers generally prefer to avoid sessions when the wind is too strong and onshore, as it spoils the regularity of the waves.
• Offshore wind: Offshore wind, on the other hand, blows from land to sea. This is the ideal wind for surfers. By blowing against the wave, it makes it smoother and cleaner, and often allows the wave to remain "open" longer, creating better conditions for tubes. A light offshore breeze can turn an ordinary day into a memorable session.
  
  

2.2. Swell: the driving force of waves

The swell is the wave generated by the wind, often far from the coast, which gives rise to waves. To understand surf forecasts, it's crucial to know how to interpret swell, as it determines wave size, power and frequency. Here are the key elements to consider:

• Swell size: Measured in meters, this indicates the height of the waves generated by the swell. A 2-meter swell can produce waves of similar size, but how these waves reach the beach depends on the geography of the seabed and the direction of the swell.
• Wave period: Expressed in seconds, it measures the time interval between two successive waves. A long period (greater than 10 seconds) means that waves are spaced out and have travelled long distances, accumulating energy. These waves tend to be more powerful and well-shaped. Conversely, a short period (less than 8 seconds) indicates a closer swell, often accompanied by smaller, disordered waves.
• Swell direction: The direction in which the swell hits a spot is crucial. Each beach has a specific geographical orientation that makes it more or less favorable to certain swell directions. A swell arriving at the right angle to the beach will produce well-shaped waves, while a wrong swell direction can make waves smaller or unstable.

2.3. Tides: the element that changes everything during the day

Tides are the result of the gravitational pull of the Moon and Sun, and they significantly influence waves. Every beach reacts differently to the tides, so it's essential to understand how the tides influence the waves on your favorite spot:

• Low tide: At low tide, some beaches reveal rocky bottoms or sandbanks which, under certain conditions, can improve wave quality by creating well-defined peaks. However, if the water is too shallow, this can make surfing more dangerous and the waves smaller.
• High tide: When the tide rises, water covers sandbanks or reefs, altering the way waves are formed. On some beaches, this can make waves softer and less powerful, while on others, it can improve wave quality by allowing a better shape.
• Rising or falling tide: Depending on the spot, some beaches offer the best surfing conditions when the tide is rising or falling, as the dynamics of the water can create more powerful and consistent waves.

2.4. Currents: invisible but powerful forces

Currents, whether the result of tides or wider water movements, have a direct impact on surfing and safety. It's essential to know how to identify and manage them:

• Rip currents: These powerful currents that form perpendicular to the beach can quickly drag surfers out to sea. Although they can sometimes be used to get out faster, they are often dangerous, especially for inexperienced surfers. Learning to spot them is crucial to safe surfing.
• Tidal currents: These currents, caused by the rise and fall of the tides, can make navigation more difficult by pulling surfers in one direction. On some spots, they can help you move through the water, but they require constant vigilance.

3. Interpreting weather forecasts for surfing

Understanding how waves form is one thing, but knowing when and where they'll be best for surfing is quite another. Surf forecasts combine different weather parameters to give you a clear idea of future conditions. It's essential to know how to read and interpret these forecasts correctly to avoid unpleasant surprises and get the most out of your sessions. Here are the key elements to analyze in a surf forecast.

3.1. Tools for consulting surf forecasts

Before going into the details of what you need to understand, it's important to know which tools to use. Numerous sites and applications provide access to accurate, detailed surf forecasts. Here are a few popular platforms:

• Magicseaweed (MSW): Widely used by surfers around the world, this site provides comprehensive forecasts, including wave size, swell period, wind direction and tides. It also offers live reports for selected spots.
• Surfline: In addition to detailed forecasts, Surfline offers live webcams on hundreds of surf spots around the world, enabling you to see conditions in real time.
• Windy: Although initially designed for wind forecasts, Windy is also an excellent tool for consulting swell and tide forecasts. Its animated maps enable dynamic visualization of swell and wind movements.
• Windguru: Mainly used by kite surfers and windsurfers, Windguru is also popular among surfers for its accurate wind and swell forecasts.
• Windfinder: Highly accurate wind direction, with a spot map showing wind direction and strength in real time!
• Surf Forecast: Very precise swell power in KJ!

3.2. Wave size and direction

Swell is the central element in any surf forecast. Here are the two most important parameters to watch:

• Swell size: Measured in meters or feet, swell size indicates the approximate height of the waves generated. However, this height can vary considerably once the swell reaches the coast, depending on local bathymetry (i.e. the shape and depth of the seabed). For example, a 2-meter swell may produce much larger waves on a reef, or smaller waves on a gently sloping beach.
• Swell direction: The direction in which the swell hits the coast is crucial in determining whether a spot will be "on fire" or whether the waves will be more difficult to surf. Each beach has a unique geographical orientation, and some beaches only work well with certain swell directions. For example, a beach facing southwest will respond better to swell coming from that same direction than to swell coming from the northeast.

3.3. Wave period

Wave period is another key indicator for understanding wave quality. It is expressed in seconds and measures the time elapsed between two successive waves. In general :

• Short period (less than 8 seconds): A swell with a short period is generally generated by nearby winds. These waves tend to be smaller, closer together and messier. These conditions are often the result of strong winds blowing locally, making surfing more difficult and less enjoyable.
• Long period (over 10 seconds): A long period indicates a swell that has traveled longer distances, accumulating more energy. Waves are then more widely spaced and well-formed, offering greater power and often longer ripples. Experienced surfers often look for periods of 12 seconds or more, as this means better wave quality.

3.4. Wind: direction and intensity

As we saw earlier, wind plays a fundamental role in wave quality. When consulting the surf forecast, it's important to keep an eye on :

• Wind direction: Wind direction is often indicated in relation to the cardinal points (north, south, east, west). An offshore wind is generally ideal because it "pushes" the waves in the right direction, making them smoother and longer. Conversely, an onshore wind degrades the shape of the waves, making them messy and less suitable for surfing.
• Wind speed: Wind speed is just as important. Too strong a wind, even if it's offshore, can make the wave difficult to surf by creating turbulence on the water's surface. Conversely, a light offshore breeze of 5 to 10 km/h is perfect for maintaining well-formed waves.

3.5. Tides: understanding their role in forecasting

The tide is another essential factor to analyze when planning your surfing session. Every beach reacts differently to tides, and it's crucial to know the specifics of your favorite spot. Here's how to understand the effect of tides:

• Rising or falling tide: The transition between low and high tide can improve wave quality, as it changes the way waves break on the shore. On some beaches, the rising tide is ideal as it offers more depth, thus improving wave power and length.
• Tide times: Forecasts often indicate the times of high and low tides. Knowing these times is essential for choosing the right moment to surf. For example, some reef waves are excellent at low tide, while other beach breaks work better at high tide.

3.6. Combining elements to choose the best time

Once you have a good understanding of the various weather factors, it's time to combine them to determine the optimum conditions for surfing. For example, if the forecast indicates :

• A 2-meter swell with a 12-second period, a moderate offshore wind and a rising tide: It's probably the perfect time to hit the water if your spot works well with these conditions.
• A small 0.5-meter swell with a short 6-second period and a strong onshore wind: It may be best to postpone your session or look for a more sheltered spot.

The art of reading surf forecasts lies in the ability to combine these elements to choose the perfect time and place. The more you pay attention to these details, the greater your chances of finding quality waves.

4. How to choose the right time to go surfing

Now that you understand how to interpret weather forecasts and the natural elements that influence wave quality, the next step is to learn how to combine this information to choose the ideal time to surf. Every surfer, every board, and every spot has different needs, which means there is no universal answer to the question "When should I go surfing?" This section will guide you in analyzing conditions based on your skill level, the type of board you use, and the type of waves you are looking for.

4.1. Optimum conditions according to board type

Each type of board is designed to work best in certain wave conditions. Here's how to choose the ideal conditions for your equipment:

• Shortboard: If you surf with a shortboard, you'll generally be looking for more powerful, well-formed waves. Shortboards work best in medium to large waves, with a longer swell period (10 seconds or more) and a light to moderate offshore wind. Shortboards are made to turn quickly and adapt to hollow waves, so a steady swell with adequate tide is essential to maximize their performance.
• Longboard: Longboards are designed for smaller, gentler waves. If you own a longboard, you can aim for smaller waves, between 0.5 and 1.5 meters, with a shorter swell period (8-10 seconds). Low to mid-tide generally works well for longboards, as it offers longer, less powerful waves, ideal for slower, more stylish maneuvers.
• Fish: Fish boards are versatile and adapt well to smaller or less powerful waves. They're perfect for days when the swell is small or messy, as their extra volume and wider design make them ideal for catching small waves. You can aim for conditions similar to those of a longboard, but with a preference for more hollow waves to make the most of the speed offered by this type of board.

4.2 Choosing the best tides for your spot

The tide has a huge effect on the way a wave breaks. Some spots work best at high tide, while others are perfect at low tide. To determine the best time of day to go surfing, it's important to know the configuration of your favorite spot.

• High tide: Reef and point break spots, where waves break over rocks or underwater formations, are often best at high tide. At this time, the water covers the reef, allowing the waves to roll cleanly without breaking too abruptly. On some sandy-bottomed beaches, high tide can also allow waves to form better by increasing the depth.
• Low tide: Some beaches with sandy bottoms and sandbanks work better at low tide, as the shallower water allows the waves to break more evenly. However, at low tide, some reefs can become dangerous as they are less covered by water, increasing the risk of injury if you fall.
• Rising or falling tide: Many experienced surfers prefer to surf when the tide is rising or falling, as these phases can generate more powerful and better-formed waves. As the water rises or falls, ocean dynamics change, creating optimal conditions for certain beaches. For example, on a point break, a rising tide can help to lengthen the wave, while a falling tide can accelerate its formation.

4.3. Adapt to your skill level

Your skill level is also a determining factor in choosing when and where to surf. If you're a beginner, it's best to choose softer conditions, while experienced surfers can tackle bigger, more powerful waves. Here are a few tips to adapt your sessions to your level:

• Beginners: As a beginner, you'll want to look for smaller waves, ideally between 0.5 and 1 meter, with a shorter swell period (8 to 10 seconds). Sandy beaches with gentle, regular waves are perfect for learning to stand up and practicing the basics. Avoid conditions where the wind is too strong or onshore, as this will make practice more difficult.
• Intermediates: Once you have some experience, you can start looking for slightly larger waves (1 to 2 meters) with a longer swell period. Rising and falling tides can offer ideal conditions for perfecting your maneuvers and learning to handle more powerful waves. You can also start exploring more challenging reef and point-break spots.
• Advanced: Advanced surfers are often looking for bigger (over 2 meters) and more powerful waves, with long swell periods (12 seconds or more). At this level, it's important to know how to interpret the forecast to find the conditions most conducive to technical maneuvers and intense sessions. Reefs and hollow waves at high or falling tide can offer spectacular tubes and ripples.

4.4. Avoid poor conditions

It's just as important to know when not to go surfing. Here are some signs that conditions might not be ideal, or even dangerous:

• Strong onshore wind: A strong onshore wind (more than 15-20 km/h) can destroy wave shape and make for a frustrating session. Waves will often be disordered, making the takeoff more difficult and the session less enjoyable.
• Swell too short or too small: A swell with too short a period (less than 6 seconds) often indicates disordered waves generated by local winds. In these conditions, it is often difficult to find quality waves. Similarly, a swell that's too small can produce insufficient waves for a satisfying session, especially if you're surfing with a shortboard or small-sized board.
• Dangerous conditions: If the forecast calls for waves over 3 meters with strong currents, it may be best to stay out of the water, especially if you're not an experienced surfer. Powerful currents, massive swells and stormy conditions can make surfing dangerous for even the most seasoned surfers.

4.5. Consider the crowd

Finally, an often overlooked but important factor: how busy the spot is. Even if conditions are perfect, an overcrowded beach can make the session less enjoyable. Try to plan your sessions early in the morning or late in the day to avoid the crowds. What's more, some more isolated or less popular spots can offer equally good waves with far fewer surfers in the water.

• The dangers of poor conditions :
  • Strong currents, unpredictable waves, strong winds.
• Safety tips :
  • How to assess conditions before entering the water.
  • Always check forecasts to avoid dangerous situations.

5. Impact of weather on surf safety

Although the main purpose of weather forecasts is to optimize the quality of your surfing sessions, they also play a crucial role in safety. Surfing can be a dangerous sport if weather and ocean conditions are not taken into account. Knowing how to recognize potential risks and understand how conditions influence your safety is an essential skill for any surfer, whatever their level.

In this section, we'll explore the main weather-related hazards, as well as tips on how to minimize the risks and surf safely.

5.1. Hazards associated with adverse weather conditions

Certain weather conditions can make surfing not only difficult, but also dangerous. Here are the main hazards to watch out for:

• Waves that are too big and powerful: Although large waves can attract experienced surfers, they also present a danger, especially for the less seasoned. Waves over 2-3 metres can quickly submerge you, dragging you underwater for several seconds. Falling into a powerful wave can cause injury or drowning if you're panic-stricken. Keeping an eye on swell and wave size is crucial, especially if you don't feel ready for more extreme conditions.
• Rip currents: Rip currents are among the most insidious hazards for surfers, especially beginners. These powerful currents form when seawater flows back out to sea through channels in the seabed. They can quickly sweep a surfer away, making it difficult to get back to shore. Even experienced surfers need to learn how to spot and avoid these currents, or how to get out of them by swimming parallel to the shore instead of fighting directly against the current.
• Stormy conditions and lightning: Surfing during a storm is extremely dangerous, especially when lightning is present. Water is an excellent conductor of electricity, which means that if lightning strikes the ocean, anything nearby can be affected. It's advisable to get out of the water immediately if lightning is visible or a storm is approaching.
• Strong onshore or offshore wind: Too much wind, whether onshore or offshore, can make for a dangerous session. Onshore wind can create messy waves that are difficult to surf, while too strong an offshore wind can make it difficult to catch a wave, constantly pushing you back out to sea. What's more, if you're too far from shore, a strong offshore wind can make getting back to shore very arduous, especially if you're exhausted.
• Cold temperatures: Cold can also be a serious hazard, especially in cooler waters or during the winter months. If you surf without a suitable wetsuit, hypothermia can set in quickly, leaving you disoriented and unable to return to shore. Always make sure you're wearing a wetsuit suitable for the water temperature, and don't prolong sessions in icy conditions, is essential to staying safe.

5.2. How to assess conditions before entering the water

Before you take to the water, it's essential to always assess the weather and ocean conditions to avoid dangerous situations. Here are a few steps to follow to assess the safety of your session:

• Check the weather forecast: Be sure to consult a detailed forecast before you go surfing. Platforms such as Magicseaweed or Surfline provide not only wave size forecasts, but also wind direction, current strength and tides. Look for conditions where the wind isn't too strong and the swell matches your skill level.
• Observe the spot before entering the water: Don't rush into the water without taking a few minutes to observe the spot. Check the size and regularity of the waves, the wind direction and any visible currents (such as bay currents). Try to spot more experienced surfers to see how they handle the conditions. If they seem to be struggling, this may indicate that the waves or currents are more difficult than expected.
• Know the local peculiarities: Every surf spot has its own particularities. Some are known for their powerful currents, others for rocky bottoms that are dangerous at low tide. Find out about the specific dangers of your spot before you go, especially if you've never surfed there before. For example, if a spot is known to have powerful waves on a reef at low tide, it may be safer to wait until the tide comes in.
• Learn to recognize bayes currents: Bayes currents are often characterized by calmer sections of water where waves don't break, or by darker, rougher water. If you notice such an area, it's best to avoid it. If you find yourself caught in a current, don't panic. Instead of swimming directly towards the shore, swim parallel to the beach to get out of the current.

5.3. Safety rules at sea

In addition to monitoring forecasts and ocean conditions, it is important to follow a few basic safety rules to minimize risks:

• Don't surf alone: Surfing in a group or with a partner is always safer. If something goes wrong, it's important to have someone close by to help or call for help.
• Be aware of your limits: Don't commit to conditions you can't control. If the waves are bigger or more powerful than you're used to surfing, it may be best to wait for calmer conditions or watch other more experienced surfers before trying your luck.
• Always wear a leash: The leash is an essential safety feature that prevents your board from moving away from you after a fall. Not only does it keep you close to your board, it also prevents it from injuring other surfers or swimmers. Always check that your leash is securely fastened before entering the water.
• Check the water temperature and wear the right wetsuit: If you're surfing in cold waters, wearing a wetsuit suitable for the temperature is essential to avoid hypothermia. In general, a wetsuit of 4/3 mm or more is recommended for cold waters, and booties, gloves or hoods may also be necessary in extreme conditions.

5.4. In the event of danger: how to react

Even with the best precautions, it's possible to encounter dangerous situations in the water. Here are a few tips on what to do in the event of a problem:

• If you're caught in a baystream: Don't panic or fight the current by swimming directly towards the shore, as this will quickly exhaust you. Swim parallel to the beach to get out of the current, then once out of the danger zone, swim gently back to shore.
• If a wave overwhelms you: If you fall into a powerful wave, stay calm. Underwater turbulence usually lasts only a few seconds. Protect your head with your arms and let the wave carry you along until you feel the water calm down before surfacing.
• If you're tired or injured: If you're tired or injured, don't take unnecessary risks. Use your board as a float and wait for a gentler wave to return quietly to shore. If you can't paddle, wave your arms to signal that you need help.