Surf Forecasts:
Siriu surf forecast from 15 Aug 2026:
- Best quality surf: Tuesday 18 Aug, 6PM (local time) - 6ft (1.9m), 9s period, NE swell with cross-offshore winds.
- Most powerful swell: Monday 17 Aug, 6PM (local time) - 7.5ft (2.3m), 9s period, NE swell with 808 kJ wave energy.
- Next surfable swell (1★+): Tuesday 18 Aug, 6PM (local time) - 6ft (1.9m), 9s period with NE 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 1.9m and 9s period with a secondary swell of 1.5m and 9s. Another secondary swell of 0.2m and 10s 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 2.3m 9s and forecast to arrive on Monday (Aug 17) at 6PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 9s period and expected on Friday (Aug 21) at 6PM.
| Wave Type | Time (-03) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6PM (Tue 18th Aug) | 6ft (1.9m) 9s |
| Best Surf | 6PM (Tue 18th Aug) | 6ft (1.9m) 9s |
| Most Powerful | 6PM (Mon 17th Aug) | 7.5ft (2.3m) 9s |
Table - best surf conditions forecast for Siriu over the next 16 days.
The Lowdown
Alright, Rusty here. Let's have a look at what's coming down the pipes.
Honestly, for the next week or so, things are looking pretty ordinary for Siriu. We're getting hit with a lot of cross and cross-onshore winds, and the swell is a bit of a mess. The first real session worth paddling out for isn't until around the 19th, but even that's just small with an average wind. You'll be waiting a while for the good stuff.
The standout session in this whole run is looking like Sunday the 23rd of August. We get a proper pulse of southerly groundswell pushing in at a very long 15 second period, with wave heights around 8 ft. The combined energy is strong at (5251), so there's plenty of power. The wind is cross-off and clean, which will clean things right up. However, this is a big swell – definitely only for experienced surfers. That long period will also make it break a bit straight on the beach, so keep your wits about you.
If that Sunday is a bit too much, the following Monday and Tuesday mornings (the 24th and 25th) are your best bets. The swell drops back a touch to 6 ft, still from the south-southeast with a solid 12-13 second period. The wind is a light offshore from the southwest, making for clean lines. The wave energy is still solid, and conditions look excellent for competent surfers.
The very end of the run, on Wednesday the 26th, shows a small drop in swell but the wind goes glassy. It will be clean but tiny, with only 3 ft waves and a weak energy reading (436). Something to keep in mind if you're desperate for a splash.
Otherwise, the rest of the time is a write-off due to poor winds and choppy conditions. The blank runs are pretty normal for this setup, but the swell on the 23rd could be worth the wait.
Rusty.
Short Range ForecastHeavy rain (total 37mm), heaviest during Fri night. Warm (max 24°C on Mon morning, min 16°C on Fri night). Mainly fresh winds. | Days 5-7 Weather SummaryMostly dry. Warm (max 29°C on Tue morning, min 18°C on Wed night). Wind will be generally light. | ||||||||||||||||||
Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | ||||||||||||||
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 12 | E 8 | ENE 8 | ENE 8 | E 8 | ENE 8 | NE 9 | ENE 9 | NE 9 | NE 8 | NE 9 | ENE 9 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 7 |
Wave Graph  | |||||||||||||||||||
 kJ | 866 | 497 | 399 | 570 | 422 | 259 | 620 | 505 | 500 | 645 | 523 | 535 | 288 | 181 | 149 | 85 | 123 | 107 | 71 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | cross-on | cross-on | cross | cross | cross | cross | cross | cross-on | cross | cross | cross-on | cross | cross-off | cross | glassy | cross-on | cross-on | off |
High Tide | 2:28AM0.79m | 3:22PM0.63m | 3:03AM0.78m | 3:38PM0.61m | 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 | ||||||
Low Tide | 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 | 9:21AM0.40m | 10:01PM0.27m | 9:02AM0.45m | 2:44PM0.49m | 10:27PM0.31m | |||||
 |  | |  |  | |  |  | |  | | | | | | | | | | |
 | — | 6:46 | — | — | 6:45 | — | — | 6:43 | — | — | 6:43 | — | — | 6:41 | — | — | 6:41 | — | — |
 | — | — | 5:52 | — | — | 5:52 | — | — | 5:52 | — | — | 5:53 | — | — | 5:53 | — | — | 5:53 | — |
mm | 30 | 3 | 2 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 17 | 17 | 18 | 18 | 21 | 21 | 19 | 24 | 24 | 20 | 29 | 29 | 22 | 27 | 25 | 19 | 25 | 25 | 21 |
Feels °C | 17 | 17 | 18 | 17 | 18 | 18 | 17 | 22 | 22 | 19 | 27 | 30 | 23 | 26 | 25 | 20 | 24 | 24 | 22 |
Swell 1 Height (m) Direction Period (s) | SSE 12 | E 7 | E 8 | ENE 8 | E 8 | E 8 | ENE 8 | ENE 8 | SSE 10 | ENE 9 | ENE 8 | ENE 8 | ENE 9 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 7 |
| kJ | 866 | 303 | 399 | 226 | 300 | 259 | 418 | 468 | 19 | 416 | 329 | 347 | 288 | 181 | 149 | 85 | 123 | 107 | 71 |
Swell 2 Height (m) Direction Period (s) | — | SSE 12 | SSE 11 | ESE 8 | SSE 10 | SSE 10 | SSE 10 | SSE 10 | SE 8 | SSE 11 | S 10 | S 10 | S 9 | S 8 | S 7 | S 7 | S 8 | S 8 | S 8 |
| kJ | — | 497 | 314 | 145 | 121 | 118 | 58 | 39 | 3 | 11 | 8 | 8 | 6 | 1 | 15 | 67 | 63 | 42 | 18 |
Swell 3 Height (m) Direction Period (s) | — | — | E 16 | SSE 11 | E 12 | E 13 | — | — | — | SE 9 | SE 9 | SE 8 | E 13 | SE 12 | SE 13 | SE 13 | SE 12 | SE 12 | SSE 7 |
| kJ | — | — | 5 | 202 | 28 | 13 | — | — | — | 3 | 3 | 3 | 4 | 6 | 7 | 7 | 6 | 6 | 9 |
Wind waves Height (m) Direction Period (s) | ESE 7 | E 7 | — | ENE 8 | ENE 8 | N 4 | ENE 8 | NE 9 | ENE 9 | NE 9 | NE 8 | NE 9 | — | — | — | — | N 4 | — | — |
| kJ | 327 | 408 | — | 570 | 422 | 10 | 620 | 505 | 500 | 645 | 523 | 535 | — | — | — | — | 9 | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 16 | 16 | 16 | 16 | 27 | 91 | 146 | 91 | 16 | 39 | 91 | 9 | 9 | 0 | 15 | 0 | 9 | 16 | 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.
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