Surf is generally created by storms out at sea, caused by low pressure systems:
If you have a weather stick you can tell what the air pressure is doing by the stick pointing up (for high pressure) and down (for low pressure). From this you get an indication of what the surf is going to do 100% naturally. In Devon in England, we currently have number of local dedicated surfers that literally swear by their stick.
As well as visually looking at the stick the activity has been monitored and compared to that of a more common barometer. The results were that the Weather Stick is astonishingly accurate!!