
Surf Forecasts:
Marosi surf forecast from 15 Sep 2026:
- Best quality surf: Wednesday 16 Sep, 2AM (local time) - 6ft (1.8m), 15s period, SW swell with cross-offshore winds.
- Most powerful swell: Sunday 20 Sep, 11PM (local time) - 7ft (2.1m), 16s period, SW swell with 2,203 kJ wave energy.
- Next surfable swell (1★+): Wednesday 16 Sep, 2AM (local time) - 6ft (1.8m), 15s period with SW swell.
Best Forecast Surf Conditions for Marosi this week:
The surf forecast for Marosi over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Wednesday (Sep 16) at 2AM. The primary swell is predicted to be 1.8m and 15s period with a secondary swell of 0.1m and 24s. Another secondary swell of 0.7m and 5s is also forecast. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Marosi in the next 16 days are 2.1m 16s and forecast to arrive on Sunday (Sep 20) at 11PM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.6m 6s period and expected on Sunday (Sep 20) at 11PM.
| Wave Type | Time (WITA) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Wed 16th Sep) | 6ft (1.8m) 15s |
| Best Surf | 2AM (Wed 16th Sep) | 6ft (1.8m) 15s |
| Most Powerful | 11PM (Sun 20th Sep) | 7ft (2.1m) 16s |
Table - best surf conditions forecast for Marosi over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s have a yarn about what’s coming up at Marosi over the next couple of weeks. Right off the bat, I’ve got to be straight with you – the first several days are a bit of a write-off for decent waves. The swell is hanging around, but the wind and conditions aren’t playing ball. Tuesday morning (the 15th) kicks off with a solid 6ft SW groundswell at 15 seconds and the combined energy is a hefty 1669 (moderate-strong), but the wind’s blowing a cross-onshore at 12 mph from the SSE, making it choppy. Water temp is sitting at 79°F – about average for this time of year, so no surprises there. It’s a reef break for advanced surfers only, and with those conditions, it’s just not happening. The score reflects that – a big fat zero for the morning and only a 1 for the afternoon. That’s poor. Wednesday through Saturday morning are all showing marginal surf with onshore or cross-onshore winds and only light breezes, but the wave comment keeps saying “poor” or “marginal,” so there’s nothing to get excited about. We’re basically staring at a week of nothing worth paddling out for.
Now, hold on, because things get interesting late in the piece. The standout window is Saturday the 26th and Sunday the 27th. On Saturday morning, Marosi gets a very long-period SSW swell at 23 seconds – that’s proper groundswell energy – and the combined energy spikes to 4171 (strong). It’s 5ft and blowing onshore from the S with a light breeze, so the morning is unknown but promising. Saturday afternoon though? That’s the one. The swell jumps to 10ft from the SSW at 20 seconds, with a combined energy of 6987 (very strong). The wind is a light cross-onshore from the SE, so it’ll be a bit bumpy but manageable. For an advanced reef break, this is going to be pumping. That’s the absolute peak of the forecast and the only day I’d call a standout – it’s big and powerful, so only for experts. Sunday morning keeps that 10ft SSW at 18 seconds, with onshore wind, energy at 5852 (very strong). It’s still all-time but you’ll want to be out early before the wind swings. The afternoon drops to 10ft but period shortens to 17 seconds, energy 4583 – still solid, but the cross-shore wind might clean it up a touch. Those two days are the real deal.
The rest of the second week has some size but nothing that hits those highs. Monday the 28th has 8ft SSW at 16 seconds (energy 2599) with onshore wind in the morning, and Tuesday the 29th afternoon sees 5ft SSW with a light cross-shore breeze and only 6 mph winds – that one could be clean but it’s much smaller. Wednesday the 30th has 6ft SSW at 16 seconds but the wind is light and cross-shore in the afternoon, energy 1647 – not a standout but a solid session if you miss the big weekend.
In short: the next week is mostly a bust. Then Saturday the 26th and Sunday the 27th fire up with massive, long-period SW groundswell. That’s your best bet by a long shot, but it’s serious juice – not a spot for beginners. Marosi is a consistent reef, but with that much energy and those periods, the sets will be long and the paddle out might be easier between them. Expect crowds sometimes. Stick to the weekend of the 26th and 27th for the real action. Rusty out.
Short Range ForecastMostly dry. Warm (max 27°C on Tue afternoon, min 23°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 27°C on Sun afternoon, min 23°C on Sun night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | Saturday 19 | Sunday 20 | Monday 21 | |||||||||||||||
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) | SW 15 | SW 15 | SW 15 | SW 15 | SW 14 | SW 15 | SSW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 18 | SW 17 | SW 16 | SW 16 | SW 15 | SW 14 | SW 14 |
Wave Graph | |||||||||||||||||||||
1650 | 1581 | 1581 | 1446 | 1307 | 1446 | 1690 | 1533 | 1285 | 990 | 907 | 661 | 676 | 581 | 609 | 1915 | 1968 | 2203 | 1801 | 1521 | 1115 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-off | on | cross-on | cross-off | on | cross | off | on | cross-on | glassy | on | cross-on | cross-off | on | cross-on | cross-off | on | cross-on | cross-off |
High Tide | 12:33PM2.52m | 00:35AM2.91m | 1:01PM2.31m | 1:01AM2.76m | 1:28PM2.08m | 1:26AM2.57m | 1:55PM1.85m | 1:51AM2.35m | 2:26PM1.61m | 2:21AM2.12m | 4:06PM1.39m | 3:25AM1.89m | 10:13PM1.62m | ||||||||
Low Tide | 6:24PM0.43m | 7:02AM0.26m | 6:47PM0.59m | 7:32AM0.44m | 7:09PM0.76m | 8:05AM0.65m | 7:28PM0.95m | 8:45AM0.89m | 7:42PM1.15m | 9:52AM1.11m | 7:20PM1.36m | 1:49PM1.12m | 1:02AM1.60m | ||||||||
5:56 | — | — | 5:56 | — | — | 5:56 | — | — | 5:54 | — | — | 5:54 | — | — | 5:54 | — | — | 5:54 | — | — | |
— | 5:59 | — | — | 5:59 | — | — | 5:59 | — | — | 5:59 | — | — | 5:59 | — | — | 5:59 | — | — | 5:59 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 27 | 25 | 26 | 27 | 26 | 26 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 25 | 27 | 25 | 26 | 27 | 26 |
Feels °C | 26 | 27 | 26 | 27 | 28 | 29 | 27 | 28 | 29 | 27 | 27 | 27 | 26 | 27 | 27 | 28 | 28 | 28 | 27 | 28 | 30 |
Swell 1 Height (m) Direction Period (s) | SW 15 | SW 15 | SW 15 | SW 15 | SW 14 | SW 15 | SSW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 17 | SW 16 | SW 16 | SW 15 | SW 14 | SW 14 |
1650 | 1581 | 1581 | 1446 | 1307 | 1446 | 1690 | 1533 | 1285 | 990 | 907 | 661 | 676 | 581 | 422 | 1915 | 1968 | 2203 | 1801 | 1521 | 1115 | |
Swell 2 Height (m) Direction Period (s) | — | — | SW 24 | SSW 21 | SSW 21 | SE 6 | SE 5 | — | SE 6 | SE 5 | SW 21 | SE 5 | SW 19 | SW 19 | SW 18 | SE 6 | — | SE 6 | SE 5 | — | SE 5 |
— | — | 22 | 45 | 45 | 33 | 22 | — | 26 | 6 | 18 | 4 | 175 | 339 | 609 | 18 | — | 38 | 29 | — | 23 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | W 16 | W 16 | SSW 5 | — | — | — | SW 22 | — | SW 20 | SE 6 | — | SE 6 | — | — | — | — | — | SW 20 |
— | — | — | 5 | 5 | 6 | — | — | — | 18 | — | 61 | 10 | — | 27 | — | — | — | — | — | 16 | |
Wind waves Height (m) Direction Period (s) | SE 4 | SE 5 | SE 5 | SE 4 | SE 5 | SE 6 | — | SE 4 | SE 6 | — | SE 6 | — | — | SE 6 | — | — | SE 5 | — | — | SE 6 | SE 5 |
19 | 56 | 27 | 12 | 56 | 77 | — | 26 | 72 | — | 16 | — | — | 21 | — | — | 34 | — | — | 25 | 67 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 134 | 282 | 0 | 134 | 137 | 0 | 134 | 284 | 0 | 134 | 137 | 0 | 20 | 137 | 0 | 134 | 137 | 0 | 134 | 137 | 0 |
Best forecast wave conditions in Sumba | |||||||||||||||||||||
Best forecast wave conditions in Indonesia | |||||||||||||||||||||
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Information about the Marosi Surf forecast
The above surf forecast table for Marosi provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Marosi can be found by selecting the local surf guide option on the grey menu. Our Marosi 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 (Marosi) 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 Marosi 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.
Are you planning a holiday in Sumba? If you are looking for accommodation near Marosi, camping, hotels and holiday cottages in Sumba, consider staying in Adalara which is 29 km (18 miles) away.










