What is a good swell period for surfing?

Anything 13 seconds or longer is quality groundswell. 10 to 12 seconds is decent, and under 8 seconds is usually weak, wind-driven surf. Period often matters more than raw swell height.

Is a bigger swell always better?

No. A smaller long-period swell in the right direction with light offshore wind will usually beat a bigger short-period swell with onshore wind. Read height, period, direction, and wind together.

What wind is best for surfing?

Light offshore wind (blowing from land to sea) is best because it holds waves up and grooms them clean. Strong onshore wind ruins otherwise good swell.

How to Read a Surf Forecast

7 min read

A surf forecast looks like a wall of numbers until you know what each one is telling you. Once you can read the four that matter, and how they interact, you can predict a good session before you leave the house.

The four numbers that matter

Every forecast, no matter the source, comes down to four inputs: swell height, swell period, swell direction, and wind. Tide sits on top of all of them. Read them together, never in isolation.

Swell height: the size of the open-ocean swell, not the wave you will ride at the beach.
Swell period: the seconds between waves. This is the quality signal most beginners ignore.
Swell direction: the compass direction the swell is travelling from.
Wind: speed and direction, which decides whether the surface is clean or blown out.

Why period matters more than height

A 3ft swell at 16 seconds will usually produce bigger, more powerful, better-organized waves than a 5ft swell at 8 seconds. Long-period swell has travelled far, carries more energy deep in the water column, and stands up cleanly on the reef or sandbar.

As a rough guide: under 8 seconds is weak, wind-driven slop; 10 to 12 seconds is decent; 13 seconds and up is groundswell worth getting excited about. Two forecasts with the same height can be completely different sessions once you read the period.

Direction: does the swell actually reach your spot?

A spot only works when the swell direction lines up with how the coastline and seabed face. A south-facing beach can be flat during a big north swell just around the headland. Learn the swell windows for your local breaks, then check whether today’s direction fits.

Wind is the make-or-break

Offshore wind (blowing from the land out to sea) holds waves up and grooms them clean. Onshore wind (from the sea toward land) crumbles them into mush. Cross-shore is somewhere in between. Even a perfect swell is ruined by strong onshore wind, and light offshore can make a small swell magic. Dawn is often best because wind is usually lightest early.

Tide ties it together

Most spots have a tide they prefer. Shallow reefs often want more water (higher tide) to be safe and to break properly; some beach breaks come alive on a pushing mid tide. There is no universal rule, which is exactly why logging your own sessions against the tide is the fastest way to learn your spot.

Putting it together

Read them as a stack: is the swell direction in my spot’s window, is the period long enough to carry real energy, is the wind light or offshore at the time I can surf, and is the tide in the range my spot likes? When all four line up, go. When you log the result, you turn each forecast into a data point that makes your next prediction sharper.