Elements that shape desirable wave riding conditions are the wind, tide, swell, and location. There is always a favorable combination of these conditions for each surf spot. All surf spots have their own unique formula, and when those variables shift into place they'll create wave riding perfection. Understanding these principles will help you choose which spot and the best time to head out for a surf.
WIND
There are three distinct types of wind conditions. Winds that blow onshore, side shore, and offshore. Start to think in terms of reading a compass when learning about how winds affect surfing. Onshore winds come from the Northwest (NW), West (W), Southwest (SW), and South (S). These are the least favorable and make for choppy bumps on the surface of the water. Side shore winds come from the North (N) and Southeast (SE) and create partially bumpy sections on the waves, making it fun to surf. Offshore winds come from Northeast (NE) and East (E) which grooms the surface of the wave making it smoother to ride on. Most of California's coastline faces South and West. The best wind for surfing will always come from the East, from the desert. These dry desert winds are called Santa Anas and last from October-February but very rarely do they happen. There are also winds known as "thermals'' which travel from the West caused by changes in pressure. West facing beaches are more exposed to thermals while South facing beaches are more sheltered and allow for better surfing conditions. Get to know the directions the wind can blow from and what direction the beaches face that you want to surf at. The relationship between the angle of the wind and the direction at which the beach is pointing toward translates into a certain condition. This takes a trained eye and built up experience to master.
TIDE
The tide ranges anywhere from -2ft to +7ft in California. There's a low tide, mid range, and high tide. Low tide is anything below 2ft. Mid tide is anything between 2ft and 4ft. High tide starts at 4ft and goes up to 7ft. The tide in a 24 hour period can change a lot or it can stay very steady depending on the time of year. People can predict the tide up to several years in advance and the tide charts are available to access online. Choosing where to surf on any given day can be done by seeing at which point the tide is incoming and outgoing. If the tide is incoming, then rock bottom waves called point breaks and sand bottomed waves called beach breaks will be the better choice. The incoming tide increases the wave size and consistency allowing for a better overall surf session. During the dropping tide, conditions at the point breaks will be enhanced whereas the beach breaks will be deteriorating. The reasoning for this is rock bottom beaches have a more intricate depth change. The lowering of the water level exposes additional complex patterns on the sea floor and thus enhances the wave shape. Beach breaks have less variations in depth change from sandbar to sandbar resulting in waves being poorly shaped. Another type of wave are reef breaks. These tend to do best on higher tides since they are positioned closer to water level. A reef is best when it's not fully exposed and the proper amount of water is covering it. Waves can throw hollow barrel sections and can be very fun on these types of breaks.
SWELL
Swells are characterized by the series of waves created from intense storms and high winds being transferred into a kinetic wave energy. Large waves are created by strong winds that blow for lengthy amounts of time and travel from far distances. Throughout the ocean, scientists have placed buoys that constantly monitor the ocean's activity. They record data as the waves push into them in the open sea. The height they lift and the time it takes between each lift determines the swell's raw power! The wave height is measured as well as the time in seconds between each wave. For example, 8ft @ 20 seconds is a reading that is on the powerful end of the swell spectrum. Anything below 15 seconds is considered a shorter period and is on the lower range of wave power. The time being recorded is referred to as the "period". Longer period swells are more powerful because the storm is pushing really high volumes of water from downwind, creating huge spaces between the peaks of the waves. Once the swell direction is tracked, wave forecasts can be developed. Every swell is unique, making it hard to predict before hitting the coastline. Even the world's best surf forecasters make mistakes and you can't always rely on the data reported weeks in advance. You are better off driving down to see the waves or checking out the webcams on Surfline in real time to identify the final outcome of the conditions. The summer months have swells coming from the South whereas the winter season has swells coming from the North. South facing beaches match best with south swells while beaches facing toward the west attract west swells. The next variable that interacts with how the swells take on a specific wave formation is the surf location.
LOCATION
All beaches are unique and there are many factors that play into how a surf spot behaves. Ocean topography and bathymetry play the biggest role in understanding the mechanics of a surf spot. Waves interact with the shape of the seafloor in a very special way. There are three basic types. Point Breaks are rock and sand bottomed stretches of coastline. Beach breaks are mainly sandy bottomed coastal areas. Then there's reef breaks which are fully rock bottomed. Point breaks are curved and less flat resembling the look of a cove or a horseshoe. They tend to favor longer period swells. Beach breaks are more flat and spread out and favor shorter period swells. Reef breaks can be curved or flat and tend to favor all types of swells. With a better understanding of the coastline's relationship with the swell, one can begin to decide where the best place to surf is. When choosing a surf spot, you want to pair the beach, wind, and tide with the swell. For example, you wake up on a hot and sunny summer morning and the wind report is onshore in the afternoon with a 3ft @ 16 seconds SW swell and a low tide heading into the evening. The wind reading is 12 mph NW and onshore at the West facing beaches but side/offshore making it really smooth and clean for all South facing beaches. The beach at Surfrider Malibu is facing SE and the point on a lowering tide helps the wave connect all the way through making great long rides. Constantly checking the data and planning around optimal conditions makes for the most rewarding sessions.
MORE RESOURCES
Data for every known surf location can be accessed on the Surfline website.
Check out Wana Surf for an in depth summary on what to expect regarding localism and beach access at certain surf spots.
If you want a lower end version of Surfline with longer range forecasting analysis abilities, head to magicseaweed.
For an easy to read overview of all the buoys in the pacific rim, from Hawaii to Alaska, you’ve got to check out 17ft.com for live buoy readings.