Siumu
Pull to refresh
Swl 3
0.6ft 16s.
8kJ
Swl 2
1.2ft 8s.
8kJ
Swl 1
6.0ft 13s.
573kJ
Wnd
16mph
17mph
Hourly Forecast
Timezone: Pacific/Apia
⏱️s.
⚡️kJ
🔮
🌒
Join Surfnerd+ to check
weekend forecasts
Wednesday 3
Thursday 4
Friday 5
Saturday 6
Sunday 7
Monday 1
to unlock wave energy
Tap any forecast cell to see the forecast arrows update on the map.
Surfnerd Logo
Join Surfnerd for free to check this forecast
Join Surfnerd to check forecasts, set your homespot, save and create spots and log your surf sessions.
Sign up with Google

Siumu surf guide

Siumu is a surf spot located in a picturesque setting, known for its deep inlet formed by freshwater that has cut into the reef. Accessing the waves involves an easy boat ride, or a 10-minute paddle for those looking to get some exercise. The waves here can deliver a range of conditions, making it a popular spot among surfers.

The surf at Siumu generally works best with a south swell direction and can handle swell sizes starting at about 2 feet (0.6 meters). The waves are predominantly lefts, breaking over live coral. On good days, surfers can expect bowly lefts that can lead to nice barrels and sharp lip lines. However, when the swell isn't ideal, the waves turn into shorter, irregular ripable walls. Mid to high tides are preferable for surfing, and the best wind direction is from the north. This spot is generally suited for intermediate surfers, but the more experienced can find some exciting barrels on the best days.

There’s also another section about 300 meters up the reef that offers more lefts, though it tends to be a bit more exposed to the wind. If you're looking to catch some good waves, Siumu has its moments, making it worth checking out when you're in the area.

Surf reports and surf forecasts nearby Siumu

Salani Right
Atua, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Tafatafa
Atua, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Nu'usafee Island
Atua, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Boulders
Upolu, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Siumu
Upolu, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Coconuts
Upolu, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Coconuts
Upolu, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Wackas
Upolu, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Special K
Upolu, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Salamumu
Aana, Samoa
Reef break
Wed 30
Thu 31
Fri 1
Sat 2
Sun 3
Mon 4
Tue 5
Wed 6
Thu 7
Fri 8
Sat 9
Sun 10
Wind certainty

Wind certainty tells you how much the weather models agree on the forecast.

  • High certainty: Models agree closely; forecast is reliable.
  • Medium certainty: Some disagreement; conditions may shift slightly.
  • Low certainty: Models diverge; treat forecast with caution.

We calculate this by comparing wind speed, gust and direction from multiple models (like GFS, ECMWF, Arome, and Harmonie) and seeing how closely they match. They are weighted, meaning that some models count more than others, depending on how good they are for a certain spot.

Readme

Welcome! If you’re new to surf forecasting, check out this quick guide.

Forecast Cheat Sheet

Short on time? Focus on wave energy. It’s the best single metric to gauge how big and powerful the waves will be.

Click any table cell to jump to that forecast hour. The map will update with forecast arrows, so you can see if wind and swell direction are lining up.

Use the table sidebar to switch units for height and speed.

Log your surf sessions to compare forecasts with real sessions and sharpen future predictions.

On the map, click a metric label to bring that arrow to the front — handy when arrows overlap.

Models and Updates

Surfnerd blends multiple global and local wind and swell models using advanced interpolation and spatial techniques to create an "ensemble" forecast. Forecasts are refreshed hourly.

Surf Predictions

Our AI-driven algorithm scores surf quality, shown by green, orange, and gray dots. Each forecast hour is rated for wind, swell, and tide quality, then combined into an overall score. Here’s the scale:

Perfect
Good
Average
Bad or No Data

Session logs also feed the algorithm — the more you log, the smarter your forecasts get.

With Surfnerd, no more "you should have been here yesterday"

Login to do spot actions
Surfnerd Logo
Join Surfnerd+ and get:
  • Weekend
    + weekday forecasts
    (vs weekdays only)
  • 12-day
    forecast range
    (vs 5-day)
  • 1-hour
    forecast steps
    (vs 3-hour)
  • Wave energy
    metric
    (power rating)
  • Secondary & tertiary
    swells
    (complete picture)
"Great Forecasts. Nothing more, nothing less."