How do tides affect surf conditions?

Tides result due to the gravitational pull of the moon. The ocean rises and falls approximately every 6 ½ to 7 hours and as a result has a major effect on wave conditions.

In 24 hours, there are approximately 2 high tides and 2 low tides. As tides change approximately every 6 ½ to 7 hours, the high and low tide will be slightly different on each day. For example, the high tide may be at 9 am today and then tomorrow, it will be at approximately 10 am.

At low tide, there is less water over a break and at high tide there is more water. The depth of the water affects wave formation. As discussed in the ‘Learn to Surf for Beginners manual’ as the swell enters shallow water, the compression of the swell forces the water to rise up until it reaches a point where the top throws over as a breaking wave.

If a particular wave is closing out at low tide, it is more likely to be breaking, with a better shape at high tide. This is because there is more water over the shore at high tide. If you check the surf and see that the waves are closing out, and you notice that it is close to low tide, you will know that it will break better later, or that it was breaking better earlier. At the higher tide, there will be more water over the surf break. Therefore, it is less likely to close-out.

The moon also has another affect on tides. Generally, when there is a full moon, or new moon, there tends to be more swell and slightly higher tides.

On an incoming tide, the waves are also assisted by the pushing effect of the tide and the waves get slightly higher and sometimes more consistent than on a dropping tide (a tide that is running out).

Usually, you will notice that it is better to surf on a mid to medium tide that is rising towards the high tide and/or for a few hours after the high tide.

Deciding whether to surf on an incoming, higher, or outgoing, lower tide depends on a number of factors including the size of the swell and the depth of the water over the break.