How to read a surf forecast

A surf forecast looks like a page of maths. It isn't. Underneath every one of them — ours included — there are only two questions:

1. Is there a wave?
2. Is it clean?

That's it. Size and cleanliness are separate things, and once you hold them apart, a forecast stops being numbers and starts being a decision. Here's the whole recipe.

Question 1 — is there a wave?

Three things decide it: how big the swell is, how far apart the waves are, and where they're coming from.

How big

We show swell height in metres, but nobody talks in metres. Surfers talk in body height, so we translate:

One honest catch: this is the swell out at sea. The wave you actually ride stands up and changes as it hits the sand — sometimes bigger, sometimes smaller. Treat height as a rough guide, not a ruler.

How far apart — the number that matters most

This is period, measured in seconds: the gap between one wave and the next. Beginners skip it. Don't — it matters more than size.

• 12 seconds and up — made by a storm far away. It travelled thousands of kilometres and arrived sorted into clean, organised lines with real push. This is the good stuff.
• 7 to 11 seconds — mixed. Often perfectly fun, especially when it's small and clean.
• Under 7 seconds — local wind chop that never organised. Quick, crumbly, closes out. We'll never call this a good day, no matter how calm it is.

Think of it like cars on a highway: same number of cars, but spaced far apart they flow; bunched up they crash into each other.

Where from

Swell comes from a direction, like wind. A beach facing west can't be hit by a swell coming from the east — it's simply blocked. Every spot on Surf Adda knows which directions can actually reach it, so a swell that's technically "out there" but can't get in doesn't count.

The label

Put those three together and every session gets one word:

The actual numbers, if you like numbers: GO needs at least 1.2 m and 12 seconds and a direction that reaches the spot. OK needs 0.8 m and a direction that reaches the spot. Gentle beginner beaches lower those floors, because a clean waist-high day there is genuinely a session.

Question 2 — is it clean?

Wind is what separates a good forecast from a wasted drive. Two things about it matter: how hard it blows, and which way relative to the beach you're standing on.

Which direction counts as "offshore" is different for every beach, because the coast bends. Goa's beaches don't face the way Odisha's do. So each spot on Surf Adda carries its own answer, measured from how that stretch of coast actually sits.

Same wind, opposite call

Here's the bit that surprises people. Because direction does so much of the work, offshore wind gets a much higher tolerance:

So every session gets a second word:

The actual numbers: under 6 knots is glassy from any direction; offshore stays glassy up to 12. Under 10 knots is semi; offshore stays semi up to 16. Above that, blown. (1 knot is about 1.85 km/h.)

One day is four surfs

We never score a whole day, because on most Indian coasts the morning is glass and the afternoon is wrecked by the sea breeze. Calling that day "good" or "bad" is wrong either way.

So every day is cut into four windows, and each one gets its own two words. We average the hours inside each window — never the day's peak — because one calm spike at 5 pm shouldn't make the whole day look good.

Small and clean beats big and messy

Now each window has a pair — OK · glassy, GO · blown, and so on. To pick the best window of a day we rank the nine combinations, and the order is Surf Adda's opinion, so here it is in the open:

Notice number 4. A small glassy dawn ranks above a bigger messy day. That's deliberate, and it's an India call: most of our coast is beginner-friendly and most of our year is small. A clean, waist-high, glassy morning is genuinely good surf here — not a failed big day. The flip side, honestly: we will never dress up a blown-out day as rideable just because the swell is big.

This is also why the dot on the map is size only. A spot can show SMALL and still have an excellent glassy window hiding inside it. Open the spot to see which one.

Reading one line

A session on Surf Adda looks like this:

That's a small, clean, rideable morning. On most Indian beaches, that's a good day.

Tide, in one paragraph

We read modelled sea level through the day and tell you whether each window is rising, falling, or sitting on a high or low, plus when the next turn is. It's a global model's estimate, not the official tide table — right for "rising through the morning," not for navigation. And we don't yet tell you which tide each spot prefers, because that changes sandbank by sandbank and we'd rather say nothing than guess.

What a forecast can't do

• It knows the ocean, not your beach. It has never seen your sandbar — local knowledge wins.
• Swell height is not the wave you ride.
• Wind forecasts drift. The sea breeze can arrive an hour or two early or late.
• A GO means "worth checking" — never a guarantee. Anyone who tells you a forecast is a guarantee is selling something.

Always look at the water yourself before you paddle out. If you're new, go with someone who knows the spot — the surf schools on every spot page do exactly that. Then pick a beach on the map and read its line.