Surf Forecasts:
Siriu surf forecast from 13 Aug 2026:
- Best quality surf: Thursday 13 Aug, 3AM (local time) - 5.5ft (1.7m), 14s period, SSE swell with cross-offshore winds.
- Most powerful swell: Friday 14 Aug, 6PM (local time) - 8ft (2.4m), 13s period, SE swell with 1,972 kJ wave energy.
- Next surfable swell (1★+): Thursday 13 Aug, 3AM (local time) - 5.5ft (1.7m), 14s period with SSE 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 Thursday (Aug 13) at 3AM. The primary swell is predicted to be 1.7m and 14s period with a secondary swell of 0.5m and 4s. Another secondary swell of 0.8m and 4s is also forecast. 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 2.4m 13s and forecast to arrive on Friday (Aug 14) at 6PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 6s period and expected on Tuesday (Aug 18) at 9AM.
| Wave Type | Time (-03) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Thu 13th Aug) | 5.5ft (1.7m) 14s |
| Best Surf | 3AM (Thu 13th Aug) | 5.5ft (1.7m) 14s |
| Most Powerful | 6PM (Fri 14th Aug) | 8ft (2.4m) 13s |
Table - best surf conditions forecast for Siriu over the next 16 days.
The Lowdown
G’day, Rusty here. We’ve got a bit of a mixed bag coming up at Siriu. The first few days aren’t offering much to get excited about, but there’s a couple of moments that’ll have you checking your boardies. The waiting game is on.
Thursday the 13th morning is the standout. Cloudy skies, a light 6 mph cross-off wind from the SSW, and the water’s pumping with a solid 6 ft SSE swell, period of 14 seconds. That’s proper groundswell energy – the combined energy is a hefty 1459. This is clean, powerful stuff, but with 6 ft, it’s really for experienced surfers only. The water temp is about average for this time of year, so a steamer is optional. That morning is the best on offer, hands down. The afternoon sees it drop off a touch with rain and a cross-shore wind.
Friday the 14th is a write-off. Onshore wind and rain all day, with a messy 6 ft to 6 ft swell. Saturday the 15th and Sunday the 16th are poor with strong cross-winds and a short-period, weak swell. The energy drops to 658 and then 438 – it’s all over the place. Monday the 17th gets a bit hairy with 7 ft to 8 ft ENE swell, but winds are strong and cross-onshore, making it choppy and unappealing. That’s for the brave or the kites.
Then we hit a dry spell. Tuesday the 18th through to Saturday the 22nd sees mostly poor conditions, with a mix of onshore winds, small swell, or clean but weak energy. On Saturday the 22nd afternoon, the period pushes to 12 seconds, but it’s a cross-shore mess.
Now, here’s the real promise. Sunday the 23rd morning is another gem. Clear skies, light 6 mph cross-off wind from the SSW, and a clean 7 ft S swell with a 9-second period. The combined energy is 1399. That’s excellent, powerful stuff for the experienced crew. That morning is the second true standout.
Monday the 24th morning is worth a look too. Glassy conditions with a light 3 mph NNE wind, 5 ft SSE swell, and a 9-second period. The energy is milder at 332, but with glassy conditions, it’ll be clean and fun for a wider range of surfers. That’s a sneaky good session.
The rest of the week into the 28th is mostly average. A few clean moments with onshore winds creeping back in, but nothing that’ll get your heart racing. The swell stays small to moderate, and the energy rarely cracks 400. The 27th afternoon has a glassy moment with a 5 ft S swell, but it’s short period.
Overall, hit Thursday the 13th morning or Sunday the 23rd morning for the best waves. The rest is a waiting game.
Rusty.
Short Range ForecastHeavy rain (total 47mm), heaviest during Thu night. Very mild (max 19°C on Thu morning, min 15°C on Wed night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 3mm), mostly falling on Sun morning. Warm (max 24°C on Mon morning, min 14°C on Tue afternoon). Mainly fresh winds. | ||||||||||||||||||
Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | ||||||||||||||
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) | SSE 12 | SSE 14 | SSE 14 | SSE 13 | SSE 13 | SSE 13 | SSE 12 | SSE 12 | ENE 8 | E 8 | E 8 | E 8 | ENE 8 | ENE 9 | NE 9 | ENE 9 | ENE 9 | S 7 | S 8 |
Wave Graph | |||||||||||||||||||
762 | 1454 | 1161 | 1139 | 931 | 1274 | 754 | 437 | 385 | 299 | 331 | 393 | 699 | 699 | 842 | 510 | 283 | 349 | 235 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross | cross-on | on | cross-on | cross-on | cross | cross | cross | cross | cross-on | cross | cross | cross-on | cross | cross-off | cross-off | cross-off |
High Tide | 1:25AM0.70m | 3:05PM0.70m | 1:55AM0.76m | 3:10PM0.66m | 2:28AM0.79m | 3:22PM0.63m | 3:03AM0.78m | 3:38PM0.61m | 3:40AM0.73m | 3:57PM0.60m | 4:19AM0.67m | 4:18PM0.58m | |||||||
Low Tide | 8:54AM-0.06m | 9:18PM0.37m | 9:28AM-0.01m | 9:33PM0.36m | 9:58AM0.07m | 9:39PM0.33m | 10:23AM0.16m | 9:19PM0.29m | 10:38AM0.26m | 9:15PM0.26m | 9:51AM0.35m | 9:35PM0.25m | |||||||
— | 6:47 | — | — | 6:46 | — | — | 6:46 | — | — | 6:45 | — | — | 6:43 | — | — | 6:43 | — | — | |
— | — | 5:51 | — | — | 5:51 | — | — | 5:52 | — | — | 5:52 | — | — | 5:52 | — | — | 5:53 | — | |
mm | 2 | — | 2 | 14 | 5 | 8 | 12 | 2 | 2 | — | 2 | 1 | — | — | — | — | — | — | — |
Temp °C | 16 | 19 | 17 | 17 | 18 | 18 | 18 | 19 | 19 | 18 | 20 | 19 | 19 | 24 | 24 | 20 | 16 | 15 | 15 |
Feels °C | 16 | 20 | 16 | 18 | 18 | 18 | 18 | 19 | 18 | 16 | 19 | 19 | 18 | 22 | 22 | 20 | 12 | 10 | 14 |
Swell 1 Height (m) Direction Period (s) | SSE 12 | SSE 14 | SSE 14 | SSE 13 | SSE 13 | SSE 13 | SSE 12 | E 8 | SSE 11 | E 8 | E 8 | E 8 | ENE 8 | ENE 8 | ENE 9 | ENE 9 | ENE 9 | ENE 9 | S 8 |
762 | 1454 | 1161 | 1139 | 931 | 1274 | 754 | 328 | 263 | 299 | 331 | 393 | 470 | 510 | 603 | 510 | 283 | 206 | 235 | |
Swell 2 Height (m) Direction Period (s) | E 7 | NE 5 | NE 5 | NE 6 | ESE 7 | ESE 7 | E 7 | SSE 12 | E 16 | SSE 11 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SSE 11 | SSE 11 | S 10 | — | ENE 9 |
1 | 5 | 6 | 8 | 142 | 181 | 215 | 437 | 5 | 156 | 82 | 83 | 59 | 19 | 23 | 22 | 8 | — | 177 | |
Swell 3 Height (m) Direction Period (s) | E 8 | — | — | — | — | — | SE 8 | — | E 15 | E 14 | — | E 13 | — | SSE 12 | — | — | — | — | — |
1 | — | — | — | — | — | 129 | — | 5 | 15 | — | 3 | — | 15 | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | NNE 4 | — | — | NE 6 | — | ESE 7 | — | NNE 5 | ENE 8 | NNE 4 | NNE 4 | NNE 5 | ENE 8 | ENE 9 | NE 9 | SW 3 | S 6 | S 7 | — |
12 | — | — | 11 | — | 247 | — | 50 | 385 | 26 | 25 | 52 | 699 | 699 | 842 | 2 | 92 | 349 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 0 | 0 | 15 | 15 | 15 | 16 | 16 | 9 | 27 | 20 | 49 | 16 | 57 | 49 | 16 | 6 | 71 | 21 | 0 |
Best forecast wave conditions in Santa Catarina - Sul | |||||||||||||||||||
Best forecast wave conditions in Brazil | |||||||||||||||||||
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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.











