Help Page and Frequently Asked Questions for Surf-Forecast.com

Below are some answers to common questions that we are asked about our surf forecasts. If you have any questions that are not covered below the feel free to email us.

What do you mean by swell sizes on your surf forecast pages?

The swell sizes are the open water wave height (measured peak to trough) close to the coastline, i.e., they are not the breaking wave height on the beach. Breaking wave heights are strongly determined by the local sea bed geometry at each individual beach or reef. For example, a 10ft (3m) swell may produce big hollow waves at an exposed reef while a short distance away more moderate crumbling waves may break at the beach because of a gentle sand profile. It is best to use the forecast to track the swells that arrive at your favoured breaks and note your surf experiences for calibration of future forecasts, i.e., take a note of the swell size, period and in particular wave energy that was forecast when you had a classic day and look for similar forecast conditions again.

How does your surf quality star rating work?

The star rating is a scale of 1 to 10 and is based on swell size and character (bigger the swell and longer the period the higher the rating), however if the wind is onshore the star rating drops in proportion to the wind speed and the colour of the star goes pale. Bright yellow 10 star is the best big surf with classic conditions and light offshore winds. Flat conditions, blown out waves in onshore winds or very strong winds in any direction will result in 0 star rating.

What is wave energy in the forecast tables and swell maps?

Wave energy (in kilo Joules, kJ) on the swell forecast tables and maps indicates the power of the predicted waves and can be the most useful guide to how powerful the surf is likely to be at your local beach / reef. It is a function of both wave size and period (the larger the waves and longer the period the greater the power). Small ocean waves with a long period can create the same size surf as larger waves with a short period but they can have the same wave energy, making it a potentially better guide to likely surf size. We would suggest making a note of the forecast wave energy on a small but surfable day and on a day that is the biggest you are happy to surf. This should give you the energy range that is in your comfort zone. As a rough guide, wave energy of 100kJ can be just about surfable at many breaks, 200-1000kJ should produce increasingly punchy waves while 1000-5,000+ can start to get really heavy and even dangerous at some breaks.

Why are offshore winds best for surfing?

When the wind is onshore it tends to blow down the crest of the wave and makes it foamy and poor to surf. Cross winds can be good if offshore and bad if onshore. Offshore winds are good at holding up the crest of the wave and tend to result in steeper clean faced waves good for surfing. If the offshore wind is too strong it can make waves difficult to catch as you get blown back when you paddle to catch them. Check out our surf forecast tables where the wind conditions in relation to the coastline of your surf break are colour coded (green=offshore).

How do you define wave period?

The period is the time gap between successive waves and the longer the period the faster the waves travel. Longer period waves have more energy than short period ones and when they hit the shore they can jack up to a greater size than their open ocean wave height would suggest. As a rough guide, wave periods of less than 9s tend to be from locally generated winds and are less likely to produce good surf.

What is the advanced surf forecast?

Beneath the regular forecast tables for local surf breaks you will see the link for advanced wave and tide information. If there is more than one weather system seawards of your chosen surf break then there is likely to be more than one swell arriving at the beach / reef. The arrival of two or more swells is very common and can lead to a frustrating surf session. Take for example that you intend to surf a good 3m (10ft) 13s period ground swell but there is a 2m (7ft) 9s period second swell forecast to arrive on the same day – when you get to the beach you may find short gaps between waves making it difficult to paddle out and frustrating lumps in the face of oncoming set waves that prevent you from dropping in. For sure you will still get some good rides but the session is less likely to be a classic if there are two significant swells arriving at the same time. Another useful component on the advanced surf forecast table is the information on wind waves – this can be used to determine the direction and size of wind chop that on occasion can ruin the shape of waves. It may be that the prevailing wind waves are blocked by a headland if they are from a particular direction or they may be forecast to arrive from a less sheltered route and create annoying lumps in the surf.

How do your Surf and Wind alerts work?

These are a free service aimed at notifying surfers, windsurfers etc. of ideal conditions at their chosen break. You can choose several different locations and fine tune the triggers (wave height, period, wind direction etc.) and also choose whether to receive full html emails or short SMS-gateway compatible ones. Below is a short video about using alerts: