Surf Forecasts:
Siriu surf forecast from 17 Aug 2026:
- Best quality surf: Sunday 23 Aug, 9PM (local time) - 10ft (3.0m), 12s period, S swell with cross-shore winds.
- Most powerful swell: Monday 24 Aug, 12AM (local time) - 11ft (3.5m), 12s period, S swell with 3,145 kJ wave energy.
- Next surfable swell (1★+): Tuesday 18 Aug, 6PM (local time) - 4.5ft (1.4m), 8s period with ENE swell.
Best Forecast Surf Conditions for Siriu this week:
The surf forecast for Siriu over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Aug 18) at 6PM. The primary swell is predicted to be 1.4m and 8s period with a secondary swell of 0.1m and 10s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Siriu in the next 16 days are 3.5m 12s and forecast to arrive on Monday (Aug 24) at 12AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 8s period and expected on Friday (Aug 21) at 12PM.
| Wave Type | Time (-03) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Tue 18th Aug) | 4.5ft (1.4m) 8s |
| Best Surf | 9PM (Sun 23rd Aug) | 10ft (3.0m) 12s |
| Most Powerful | 12AM (Mon 24th Aug) | 11ft (3.5m) 12s |
Table - best surf conditions forecast for Siriu over the next 16 days.
The Lowdown
G'day, I'm Rusty. Let's have a look at what's coming down the line at Siriu over the next couple of weeks.
We've got a bit of a slow start, but don't write it off just yet. The first week is mostly a write-off for a decent paddle, with a heap of days where the wind just messes things up or the swell's too ordinary. From Monday the 17th right through to late Friday the 21st, you're looking at a tough run of messy, messy conditions. The combined energy is weak to moderate, with values in the hundreds (729 down to 106), but the wind is either cross, cross-on, or just too strong, leaving a lumpy, choppy mess. There's a glimmer on Friday morning the 21st with a clean-ish cross-off wind and a small 3ft ENE swell, but it's really just a "you could, but why would you" kind of moment. The break is fairly consistent and exposed to the east, so it does pick up swell, but the wind just isn't playing ball for the first five days.
Things start to look up on Saturday the 22nd. The morning is the standout of this early period. We get a glassy, almost dead calm start with a clean 4ft swell from the south at a 10-second period. The combined energy is moderate (347). The water temp is about average for this time of year. The break is Siriu (Romania) – a beginner-friendly beach setup that's fairly consistent and sometimes has a few people out. This Saturday morning is a genuine chance for a smooth, clean session on a longboard or funboard. The afternoon gets a bit more cross-shore and choppier.
Sunday the 23rd sees the swell really kick in, with a 8ft to 8ft southerly swell (period 9-11 seconds) and combined energy jumping into the strong range (1674 to 2603). But here’s the catch – the wind goes onshore and cross-on, and the forecast mentions the swell might be too big for this break. By Monday the 24th, it's a solid 10ft southerly groundswell with a 12-second period, and the combined energy is very strong (2275). The morning has a clean cross-off wind, but this is expert territory only – too big for beginners and probably more interesting for kite surfing than a paddle.
Tuesday the 25th is another absolute cracker. We get a glassy, dead calm morning and afternoon with a clean 5ft swell from the south-southeast at an 11-second period. The combined energy is moderate (557 to 533). The wind is zero – just pure glass. This is your second true standout. Perfect for a smooth, relaxing session. The long period (over 11 seconds) means longer lulls, but the wave shape should be good for this beach break.
The run from Wednesday the 26th to Friday the 28th of August drops off again – messy wind, smaller swell, poor conditions. It's a gap of a few days where it's not worth the effort.
Then we get a couple of promising days to finish the window. Saturday the 29th afternoon shows a clean cross-off wind with a 5ft south swell (8 seconds), moderate energy (341), and an "expect good conditions" note. Sunday the 30th is marginal but has a longer 11-second period south swell, though the wind is cross-shore.
The real highlight of the second week – and the best prospect overall for the whole 16-day window – is Monday the 31st of August. The morning is clean with a light cross-off wind and a 5ft swell from the southeast at a 10-second period. Combined energy is solid moderate (733), and the conditions are flagged as "expect very good surf conditions." This is shaping up to be the pick of the bunch for the whole outlook. Long period, clean, decent size – that's what you wait for.
Tuesday the 1st of September also looks clean and promising with a 5ft southeasterly groundswell and gentle cross-off wind, so the good run may extend if the forecasts hold.
So, to wrap it up: the first week is mostly a bust until Saturday the 22nd morning and Tuesday the 25th. The second week has a bit more promise, with Monday the 31st of August being the real standout. Keep an eye on that one.
Rusty.
Short Range ForecastMostly dry. Warm (max 31°C on Tue afternoon, min 18°C on Sun night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 25°C on Thu morning, min 13°C on Fri night). Wind will be generally light. | ||||||||||||||||||
Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | ||||||||||||||
Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map | |||||||||||||||||||
Wave Height (m) Direction Period (s) | ENE 8 | ENE 8 | ENE 8 | NE 8 | NE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 7 | ENE 7 | S 9 | S 9 | S 10 | S 9 | S 9 |
Wave Graph | |||||||||||||||||||
531 | 344 | 403 | 569 | 470 | 287 | 202 | 149 | 105 | 81 | 101 | 58 | 84 | 94 | 537 | 184 | 262 | 306 | 708 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross-on | cross | cross | cross | glassy | cross | cross-on | glassy | cross | cross-on | cross-off | cross-off | cross | cross-off | glassy | cross | cross |
High Tide | 3:40AM0.73m | 3:57PM0.60m | 4:19AM0.67m | 4:18PM0.58m | 5:03AM0.59m | 4:39PM0.55m | 6:01AM0.51m | 12:32PM0.51m | 11:59PM0.31m | 12:33PM0.57m | 11:21PM0.37m | 12:43PM0.63m | 11:30PM0.44m | ||||||
Low Tide | 9:19PM0.29m | 10:38AM0.26m | 9:15PM0.26m | 9:51AM0.35m | 9:35PM0.25m | 9:21AM0.40m | 10:01PM0.27m | 9:02AM0.45m | 2:44PM0.49m | 10:27PM0.31m | 10:38PM0.37m | 4:12AM0.25m | 6:30PM0.40m | ||||||
— | 6:43 | — | — | 6:43 | — | — | 6:41 | — | — | 6:41 | — | — | 6:39 | — | — | 6:39 | — | — | |
— | — | 5:52 | — | — | 5:53 | — | — | 5:53 | — | — | 5:53 | — | — | 5:54 | — | — | 5:54 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 |
Temp °C | 19 | 23 | 24 | 20 | 30 | 31 | 23 | 22 | 22 | 18 | 25 | 25 | 22 | 19 | 19 | 15 | 16 | 15 | 13 |
Feels °C | 17 | 21 | 22 | 19 | 29 | 31 | 24 | 23 | 24 | 20 | 23 | 24 | 21 | 15 | 15 | 12 | 14 | 11 | 10 |
Swell 1 Height (m) Direction Period (s) | ENE 8 | ENE 8 | SSE 10 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 7 | ENE 7 | S 9 | S 9 | S 10 | ENE 9 | S 9 |
348 | 344 | 20 | 351 | 315 | 287 | 202 | 149 | 105 | 81 | 101 | 58 | 84 | 94 | 245 | 184 | 262 | 84 | 421 | |
Swell 2 Height (m) Direction Period (s) | SSE 10 | SSE 10 | SE 8 | SSE 11 | S 10 | S 10 | S 9 | S 9 | S 8 | S 7 | S 10 | S 9 | S 8 | S 8 | ENE 8 | ENE 9 | ENE 8 | SSE 15 | ENE 8 |
80 | 39 | 3 | 11 | 8 | 2 | 2 | 2 | 5 | 33 | 90 | 38 | 21 | 11 | 167 | 168 | 80 | 22 | 40 | |
Swell 3 Height (m) Direction Period (s) | E 13 | E 12 | — | SE 9 | SE 9 | SE 8 | SE 8 | SE 13 | S 3 | S 11 | SE 12 | SE 6 | SE 5 | SE 5 | — | — | S 16 | — | SSE 13 |
13 | 3 | — | 3 | 3 | 3 | 2 | 6 | 1 | 21 | 6 | 5 | 5 | 1 | — | — | 5 | — | 92 | |
Wind waves Height (m) Direction Period (s) | ENE 8 | NNE 8 | ENE 8 | NE 8 | NE 8 | N 4 | SSW 3 | S 4 | SSW 3 | — | NNE 4 | NE 5 | NNW 4 | SSW 4 | S 9 | — | — | S 9 | S 9 |
531 | 343 | 403 | 569 | 470 | 40 | 2 | 2 | 2 | — | 19 | 25 | 5 | 6 | 537 | — | — | 306 | 708 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 91 | 91 | 101 | 91 | 43 | 9 | 0 | 15 | 25 | 0 | 16 | 16 | 0 | 0 | 72 | 0 | 0 | 38 | 10 |
Best forecast wave conditions in Santa Catarina - Sul | |||||||||||||||||||
Best forecast wave conditions in Brazil | |||||||||||||||||||
Header Global | |||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)
Wind Speed (km/h)
Information about the Siriu Surf forecast
The above surf forecast table for Siriu provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Siriu can be found by selecting the local surf guide option on the grey menu. Our Siriu surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Siriu) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).
Further information to help with frequently asked questions about our surf forecast for Siriu may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.
Siriu is 27 km (17 miles) from Imbituba. If you plan a holiday in Santa Catarina - Sul, look for hotels and other accommodation in Imbituba. Imbituba has rooms for a wide range of budgets as well as car hire and transport links.











