A surfer on a breaking wave at Kerewe Right, West Sumba
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Marine Weather

Swell, wind and sea temperature for five coasts around Sumba.

Kerewe Right, West Sumba

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The figures come from a marine model and refresh about once an hour. They describe the open water at each coordinate, not the take-off on a reef. Ask someone on the beach before you paddle out or dive.

Forecast model, updated recently

A modest swell of 0.9 m is coming from the southwest on a 11-second period. Wind is 16 km/h from the southeast — cross-shore at Nihiwatu.

Monday, 2 November 2026 · WITA

Primary swell

Medium-period swell

Mixed

0.9 m Height of the main swell

N E S W

SW · 228° 11 sec period From the southwest

Secondary swell
0.6 m · S · 4 sec
Wind waves
0.4 m · SE · 3 sec
All waves together
1.2 m

Three parts of the same sea They can arrive together.

  1. Main swell Longer waves that have travelled in from a distant storm.
  2. Secondary swell A smaller set from another direction. Its period is often different.
  3. Wind waves Short, steep waves raised by the wind on the spot.

At the surface

Weather and wind

Overcast

Air temperature
26°C
Wind
16 km/h from the southeast
Gusts
29 km/h
Rain
0.0 mm

Through the day

Hours on the water

06:00Early
09:00Morning
12:00Midday
15:00Afternoon
18:00Evening
Swell
0.9 m11 sec · SW
0.8 m11 sec · SW
0.8 m11 sec · SW
0.8 m11 sec · SW
0.8 m11 sec · SW
Wind
16 km/hSE · cross-shore
16 km/hSE · cross-shore
18 km/hSE · cross-shore
19 km/hSE · cross-shore
13 km/hE · cross-shore
Water
28.5°Cwarm
28.6°Cwarm
28.9°Cwarm
29.0°Cwarm
28.9°Cwarm

Swell direction is where the waves come from. Current direction is where the water is going. Offshore and onshore are judged from the way each coast faces the sea; a point further along the reef can differ.

In the water

Sea temperature

28.6°C

0.5 km/h toward the northwestOcean current, modelled

Warm sea.

Looking ahead

Wind stays in a similar range

From 06:00 to 18:00 the wind runs from 13 to 19 km/h.

  • Cross-shore wind
  • 11-second period
  • Confirm the entry locally

Wave, sea temperature and current from the Open-Meteo Marine API. Wind, rain and air temperature from the Open-Meteo weather model. This is a model, not a buoy, and not a substitute for a local briefing.

The coast, in pictures

These photographs are from the Sumba.Travel library. They show the shoreline. They are not a picture of the hour in the forecast above.

Pero Lefts, on the south coast
Pero Lefts, on the south coast © Markus Kammermann
Pinnacles, a reef wave in West Sumba
Pinnacles, a reef wave in West Sumba © Kanenori
Cliffs and a short fetch of whitewater on the west coast
Cliffs and a short fetch of whitewater on the west coast © Sumba.travel
Common questions

Reading the marine forecast

What the model includes, and what it leaves to someone on the beach.

What do these figures describe?

They are an hourly model of the open water at five coordinates: Nihiwatu, Kerewe, Mandorak, Kalala and the north coast near Tambolaka. The model is not a buoy, and it is not a report from someone standing on the reef.

How often does the page update?

About once an hour, in Central Indonesia Time (WITA). The line under the coast name shows when the stored forecast was last refreshed.

What is the difference between swell and wind waves?

The main swell is the longer set that has travelled in from a distant storm. Wind waves are short and steep, raised by the wind on the spot. A secondary swell is a smaller set from another direction. The combined wave height is the model’s single figure for that point, so it is often a little higher than the main swell alone.

What does offshore mean here?

Wind direction is where the wind comes from. Offshore means that wind is blowing from the land out to sea, judged from the way that coast faces the water. Nihiwatu faces southwest, Mandorak faces west, Kerewe and Kalala face south, and the north coast faces north. A take-off further along the same reef can feel different.

Can I use this to decide whether to surf or dive?

Use it to see the shape of the day: swell size and period, wind, sea temperature and current. It does not include tide, visibility, or the channel beside a reef. Ask someone who is on the beach that morning. For the places themselves, see the surfing guide and the diving guide.