Surf Forecasts:
Praia de Sao Marcos surf forecast from 6 Aug 2026:
- Most powerful swell: Sunday 9 Aug, 6AM (local time) - 4ft (1.2m), 5s period, NE swell with 82 kJ wave energy.
Best Forecast Surf Conditions for Praia de Sao Marcos this week:
The most powerful waves expected at Praia de Sao Marcos in the next 16 days are 1.2m 5s and forecast to arrive on Sunday (Aug 09) at 6AM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (-03) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 6AM (Sun 9th Aug) | 4ft (1.2m) 5s |
Table - best surf conditions forecast for Praia de Sao Marcos over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s be straight with you—this outlook for the next 16 days is a tough one. We’ve only got one break on the radar, Praia de Sao Marcos, and the news ain’t great.
Right off the bat, we’ve got a stretch of real poor conditions. From Thursday the 6th of August all the way through to the end of the second week, the models are showing nothing but choppy, cross-onshore slop. The swell is hanging around the 3 ft to 4 ft mark, but it’s coming from NE and ENE with a short, weak period of just 4 to 5 seconds. The combined swell energy is weak, sitting between 20 and 110 (moderate energy at its best). The wind is a constant problem—mostly cross or cross-onshore, moderate to fresh breeze, which is making a mess of the surface. There’s no clean, glassy window in sight.
The water temperature is 83°, which is a touch warmer than normal for this time of year, but that’s the only nice thing I can say.
The only flicker of hope comes right at the tail end. On Wednesday the 19th of August, we get a slight shift. The morning shows a cross-offshore wind from the E at 12 mph, with the swell nudging up to 5 ft from ENE, and the period stretching to 6 seconds. The combined energy jumps to 103 (moderate energy). The description says "clean," which is the first time we’ve seen that word. This is the best on offer, but it’s a long way off and the swell is still pretty short-period for a beach break. It’s a beginner-plus spot, so that 5 ft is manageable, but the quality is still a question mark.
The truth is, this is a blank run of surf. There’s not a single day I’d be itching to paddle out. If you’re a kitesurfer, the constant cross-onshore wind and the lumpy, choppy conditions might be more your speed, but for paddle surfing, this is a drought. Forecasts can change, but right now, I’d keep the board in the car.
Rusty.
Short Range ForecastLight rain (total 4mm), mostly falling on Thu morning. Warm (max 28°C on Thu morning, min 26°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 27°C on Sun morning, min 26°C on Sun morning). Wind will be generally light. | ||||||||||||||||||||
Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | |||||||||||||||
AM | PM | 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) | NE 5 | ENE 5 | NE 5 | ENE 5 | ENE 5 | NE 5 | ENE 5 | ENE 5 | NE 5 | ENE 5 | ENE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 4 | ENE 5 | NE 4 |
Wave Graph  | |||||||||||||||||||||
 kJ | 51 | 50 | 31 | 61 | 61 | 60 | 67 | 77 | 76 | 72 | 77 | 53 | 51 | 60 | 41 | 37 | 21 | 21 | 20 | 27 | 16 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross | cross-on | cross-on | cross | cross-on | cross-on | cross | cross-on | cross-on | cross | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross-on | cross-on |
High Tide | 12:45PM5.26m | 1:08AM5.30m | 2:00PM5.09m | 2:25AM5.22m | 3:22PM5.10m | 3:45AM5.33m | 4:36PM5.31m | 4:56AM5.59m | 5:38PM5.61m | 5:55AM5.91m | 6:30PM5.91m | 6:46AM6.18m | 7:16PM6.16m | ||||||||
Low Tide | 6:57PM1.57m | 7:35AM1.31m | 8:08PM1.74m | 8:51AM1.35m | 9:24PM1.71m | 10:05AM1.19m | 10:35PM1.48m | 11:11AM0.91m | 11:37PM1.14m | 12:07PM0.61m | 00:30AM0.79m | 12:57PM0.38m | 1:18AM0.52m | ||||||||
 |  |  |  | | | |  | |  | |  | | | | | | | | | | |
 | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — |
 | — | 6:02 | — | — | 6:02 | — | — | 6:02 | — | — | 6:02 | — | — | 6:02 | — | — | 6:02 | — | — | 6:02 | — |
mm | 2 | 1 | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 2 | — |
Temp °C | 28 | 28 | 26 | 27 | 27 | 26 | 28 | 27 | 26 | 27 | 27 | 26 | 27 | 27 | 26 | 27 | 27 | 26 | 27 | 27 | 26 |
Feels °C | 28 | 29 | 28 | 27 | 27 | 27 | 29 | 26 | 26 | 28 | 27 | 26 | 27 | 27 | 28 | 28 | 28 | 29 | 29 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | NE 9 | NNE 8 | NE 8 | — | — | NE 9 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 3 | 7 | 3 | — | — | 3 | — |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | NE 5 | ENE 5 | NE 5 | ENE 5 | ENE 5 | NE 5 | ENE 5 | ENE 5 | NE 5 | ENE 5 | ENE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 5 | NE 4 | ENE 5 | NE 4 |
| kJ | 51 | 50 | 31 | 61 | 61 | 60 | 67 | 77 | 76 | 72 | 77 | 53 | 51 | 60 | 41 | 37 | 21 | 21 | 20 | 27 | 16 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 1292 | 1974 | 1119 | 1329 | 2267 | 2314 | 1328 | 2314 | 2041 | 1329 | 1974 | 1974 | 1329 | 1963 | 1430 | 2266 | 2266 | 2266 | 2067 | 2027 | 1963 |
Best forecast wave conditions in Maranhão | |||||||||||||||||||||
Best forecast wave conditions in Brazil | |||||||||||||||||||||
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Information about the Praia de Sao Marcos Surf forecast
The above surf forecast table for Praia de Sao Marcos provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Praia de Sao Marcos can be found by selecting the local surf guide option on the grey menu. Our Praia de Sao Marcos 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 (Praia de Sao Marcos) 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 Praia de Sao Marcos 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.
Praia de Sao Marcos is 8 km (5 miles) from the city of Itaqui. If you plan a holiday in Maranhão, look for hotels and other accommodation in Itaqui. Itaqui has rooms for a wide range of budgets as well as car hire and transport links.
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