Surf Forecasts:
Siriu surf forecast from 13 Sep 2026:
- Best quality surf: Thursday 17 Sep, 12AM (local time) - 6ft (1.9m), 12s period, SSE swell with cross-offshore winds.
- Most powerful swell: Thursday 17 Sep, 12AM (local time) - 6ft (1.9m), 12s period, SSE swell with 995 kJ wave energy.
- Next surfable swell (1★+): Sunday 13 Sep, 6AM (local time) - 5ft (1.5m), 7s period with S 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 Sunday (Sep 13) at 6AM. The primary swell is predicted to be 1.5m and 7s period with a secondary swell of 1.2m and 7s. Another secondary swell of 0.5m and 8s 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 1.9m 12s and forecast to arrive on Thursday (Sep 17) 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 1.3m 7s period and expected on Sunday (Sep 13) at 12PM.
| Wave Type | Time (-03) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Sun 13th Sep) | 5ft (1.5m) 7s |
| Best Surf | 12AM (Thu 17th Sep) | 6ft (1.9m) 12s |
| Most Powerful | 12AM (Thu 17th Sep) | 6ft (1.9m) 12s |
Table - best surf conditions forecast for Siriu over the next 16 days.
The Lowdown
Alright, Rusty here again. Let’s talk Siriu in feet and miles per hour.
We’re starting slow. Sunday the 13th is a write-off — weak 3ft SE swell at 7 seconds, combined energy only 108, and messy conditions. Nothing doing. Monday the 14th improves: a clean 4ft S swell with a longer 11-second period and moderate energy (393). The cross-off wind from the SW keeps it tidy. Tuesday the 15th morning offers a similar 4ft E swell (375 energy) with clear skies and a gentle cross-off breeze — surfable but not a standout.
The best early window is Wednesday the 16th morning. Siriu sees a clean 5ft S swell at 8 seconds, combined energy jumps to 738, and a gentle cross-off breeze from the SSW. That’s solid waist-to-chest high, clean, and fun. Water temp is about average for the season.
Thursday the 17th morning brings a 5ft S swell with an 11-second period and moderate energy (555), but the wind is a light cross-shore from the north. Workable but not as clean. From Friday the 18th through Sunday the 20th, the swell drops and winds turn onshore or cross-onshore — poor quality. A gap of several days with no real recommendations.
Monday the 22nd afternoon offers hope: a 5ft ENE swell with combined energy of 298 and a cross-off breeze from the NNW, giving clean conditions. Wednesday the 23rd is blown out by strong SW winds. Then Thursday the 24th morning delivers a bigger 6ft S swell with a 10-second period and very strong combined energy of 1441 — overhead surf, but marginal due to tide, and moderate cross-off wind keeps it from being perfect. Only for experts.
Friday the 25th and Saturday the 26th see the swell back to 4ft to 2ft with clean but weaker conditions. Late September holds inconsistent waist-high ENE swells with onshore winds often. Nothing special.
Best bets: Wednesday the 16th morning for clean fun waves, and maybe Thursday the 24th morning if you’re keen on a bigger, more challenging swell. Keep watching.
Rusty.
Short Range ForecastModerate rain (total 19mm), heaviest on Mon night. Very mild (max 18°C on Tue morning, min 12°C on Mon night). Mainly fresh winds. | Days 5-7 Weather SummaryMostly dry. Warm (max 21°C on Fri morning, min 12°C on Wed night). Wind will be generally light. | ||||||||||||||||||
Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 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) | S 7 | SE 7 | S 7 | S 12 | S 11 | S 11 | ENE 7 | E 8 | E 8 | S 7 | S 8 | S 8 | SSE 12 | S 11 | SSE 11 | SSE 10 | SSE 10 | SSE 9 | NE 6 |
Wave Graph  | |||||||||||||||||||
 kJ | 257 | 73 | 99 | 106 | 284 | 269 | 140 | 186 | 157 | 240 | 290 | 273 | 995 | 516 | 452 | 333 | 166 | 124 | 130 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross-off | cross-off | cross | cross-off | cross | cross-on | cross-off | cross | cross | cross |
High Tide | 2:14AM0.81m | 2:36PM0.66m | 2:48AM0.78m | 2:54PM0.65m | 3:23AM0.73m | 3:13PM0.63m | 4:00AM0.66m | 3:33PM0.60m | 4:42AM0.58m | 3:51PM0.57m | 5:37AM0.51m | 12:07PM0.54m | 11:52PM0.30m | ||||||
Low Tide | 9:19AM0.14m | 8:48PM0.21m | 9:36AM0.23m | 8:47PM0.18m | 9:26AM0.32m | 8:54PM0.17m | 8:51AM0.38m | 9:10PM0.18m | 8:38AM0.43m | 9:29PM0.22m | 8:21AM0.46m | 2:52PM0.52m | 9:45PM0.29m | ||||||
 |  |  | | | |  |  | |  | | | | | | |  | | | |
 | — | 6:15 | — | — | 6:13 | — | — | 6:11 | — | — | 6:11 | — | — | 6:09 | — | — | 6:09 | — | — |
 | 6:05 | — | 6:06 | — | — | 6:06 | — | — | 6:07 | — | — | 6:07 | — | — | 6:07 | — | — | 6:07 | — |
mm | 2 | — | 2 | 4 | 2 | 3 | 6 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 16 | 15 | 15 | 14 | 14 | 14 | 13 | 18 | 17 | 15 | 17 | 16 | 14 | 18 | 19 | 15 | 21 | 21 | 18 |
Feels °C | 12 | 12 | 12 | 12 | 12 | 12 | 11 | 14 | 12 | 12 | 12 | 10 | 10 | 14 | 14 | 12 | 18 | 18 | 17 |
Swell 1 Height (m) Direction Period (s) | E 8 | SE 7 | SE 6 | SE 7 | S 11 | S 11 | ENE 7 | E 8 | E 8 | S 7 | S 8 | E 8 | SSE 12 | S 11 | SSE 11 | SSE 10 | ENE 6 | SSE 9 | SSE 9 |
| kJ | 48 | 73 | 41 | 79 | 284 | 269 | 140 | 186 | 157 | 134 | 191 | 88 | 995 | 516 | 452 | 333 | 49 | 124 | 96 |
Swell 2 Height (m) Direction Period (s) | S 11 | E 8 | ENE 8 | S 7 | SE 8 | SE 8 | SE 8 | SSE 8 | SE 8 | E 8 | E 8 | SSE 14 | E 8 | E 8 | E 8 | E 7 | SSE 10 | SE 12 | E 6 |
| kJ | 2 | 32 | 50 | 47 | 78 | 75 | 107 | 94 | 54 | 100 | 140 | 38 | 46 | 29 | 18 | 9 | 166 | 53 | 39 |
Swell 3 Height (m) Direction Period (s) | — | S 13 | S 12 | S 12 | E 8 | E 8 | SSE 10 | SE 9 | SSE 10 | SSE 12 | SSE 11 | SE 9 | SE 9 | E 11 | ESE 11 | ESE 10 | SE 12 | ESE 10 | NE 6 |
| kJ | — | 3 | 11 | 106 | 31 | 33 | 96 | 95 | 83 | 189 | 117 | 3 | 3 | 10 | 12 | 11 | 71 | 18 | 33 |
Wind waves Height (m) Direction Period (s) | S 7 | SSW 7 | S 7 | — | — | — | SSW 4 | S 5 | S 6 | S 7 | S 8 | S 8 | — | — | NE 2 | NNE 4 | N 4 | NE 6 | NE 6 |
| kJ | 257 | 77 | 99 | — | — | — | 18 | 13 | 109 | 240 | 290 | 273 | — | — | 1 | 9 | 10 | 66 | 130 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 13 | 10 | 13 | 0 | 0 | 0 | 0 | 0 | 38 | 0 | 0 | 38 | 0 | 6 | 57 | 20 | 25 | 27 | 6 |
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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