Surf Forecasts:
Number Fours surf forecast from 16 Aug 2026:
- Best quality surf: Thursday 20 Aug, 2AM (local time) - 1.5ft (0.5m), 16s period, SW swell with cross-offshore winds.
- Most powerful swell: Sunday 16 Aug, 2AM (local time) - 15ft (4.5m), 10s period, E swell with 4,335 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 2AM (local time) - 1.5ft (0.5m), 16s period with SW swell.
Best Forecast Surf Conditions for Number Fours this week:
The surf forecast for Number Fours over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Aug 20) at 2AM. The primary swell is predicted to be 0.5m and 16s period with a secondary swell of 0.7m and 8s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Number Fours in the next 16 days are 4.5m 10s and forecast to arrive on Sunday (Aug 16) at 2AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 7s period and expected on Friday (Aug 21) at 8PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Thu 20th Aug) | 1.5ft (0.5m) 16s |
| Best Surf | 2AM (Thu 20th Aug) | 1.5ft (0.5m) 16s |
| Most Powerful | 2AM (Sun 16th Aug) | 15ft (4.5m) 10s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright, Rusty here, looking at the charts for our spot. Let’s get into it.
Straight up, Number Fours is our only game in town according to what I’m seeing, but it’s no kind of party for the first week or so. The early days are a write-off. Sunday the 16th is just nasty – 22 mph cross-onshore winds and a lumpy 10 ft of messy ENE windswell. Do not even bother paddling out. That energy reading of 1910 tells you there’s power, but it’s all wrong. The rest of that week is all about periods of clean water but tiny surf – we’re talking 2 ft to 3 ft of weak, long-period swell. That 14 to 18-second groundswell looks pretty on paper, but it’s just not wrapping in with any size. You’d be bobbing around on a paddleboard more than catching a wave. Clean conditions though, with light breezes on the 20th, but it’s just not enough.
Now here’s where it gets interesting. We’ve got a dry spell, then things start to build from the 25th of August. The end of the month is where the focus is. From the 25th morning, the swell starts picking up – 6 ft of clean, cross-off ENE swell, and that energy jumps to 725. It stays in that 5 ft to 8 ft range right through to the 28th. The standout? I’m looking at Friday the 28th. The swell holds at 8 ft from the ENE, with a period bumping to 8 seconds, and the energy hits 1111 – that’s a solid pulse. And we’ve got cross-off winds keeping it clean. That’s the one moment in this whole run where it all comes together alright. But it’s pushing into that expert territory. Over 8 ft is no joke, especially at a reef break. The direction is ENE, and Number Fours likes it from the SSE for optimum. So it’s not the perfect direction, but 8 ft with clean cross-off winds is gonna produce some thick, barreling walls for the crew who can handle it.
The very end of the month, the 30th, sees another spike – 10 ft from the E with energy at 2348. That’s a strong signal from the ocean. But again, it’s a big, powerful swell with cross-off winds. It’ll be a heavy, full-on day for experts only, and the crowd factor here is “sometimes,” so you might have the place to yourself if you’re keen and skilled. Let’s be real though, that longer period swell (9 seconds is not that long for a groundswell) and the direction not being perfect means it won’t be a classic Number Fours day.
Overall, the next couple of weeks are a slow burn. You’re waiting until the last week of August for anything with real push. The real standout is that Friday the 28th. The other late-month pulses on the 29th and 30th are big but bordering on too wild for most.
The water temp anomaly isn’t flagged as extreme, so call it average for the time of year at Number Fours.
Stay patient. The surf will come.
Rusty.
Short Range ForecastHeavy rain (total 65mm), heaviest during Sun morning. Warm (max 27°C on Sun afternoon, min 25°C on Sat night). Winds decreasing (near gales from the ENE on Sat night, light winds from the ENE by Sun night). | Days 5-7 Weather SummaryMostly dry. Warm (max 26°C on Wed afternoon, min 24°C on Wed night). Wind will be generally light. | ||||||||||||||||||
Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | ||||||||||||||
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) | E 10 | ENE 9 | ENE 9 | ENE 8 | ENE 8 | S 14 | ENE 7 | S 13 | S 13 | ENE 9 | SW 16 | E 8 | SW 16 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 |
Wave Graph | |||||||||||||||||||
4335 | 1302 | 754 | 404 | 276 | 260 | 170 | 165 | 119 | 193 | 144 | 100 | 129 | 207 | 200 | 274 | 295 | 264 | 322 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross | cross-off |
High Tide | 6:57AM0.47m | 6:24PM0.45m | 7:54AM0.49m | 6:52PM0.37m | 8:59AM0.51m | 7:16PM0.30m | 10:13AM0.53m | 11:25AM0.56m | 10:11PM0.21m | 12:25PM0.59m | 00:08AM0.21m | ||||||||
Low Tide | 00:30AM0.05m | 12:43PM0.20m | 00:58AM0.06m | 1:59PM0.25m | 1:27AM0.08m | 3:56PM0.27m | 2:01AM0.10m | 2:47AM0.12m | 8:27PM0.20m | 8:41PM0.17m | |||||||||
— | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | |
7:00 | — | 7:00 | — | — | 7:00 | — | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:57 | — | |
mm | 19 | 37 | 8 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 26 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 25 | 26 | 25 | 26 | 26 | 26 | 26 | 26 | 26 |
Feels °C | 20 | 25 | 27 | 27 | 25 | 25 | 24 | 24 | 24 | 24 | 24 | 26 | 26 | 28 | 27 | 28 | 28 | 28 | 29 |
Swell 1 Height (m) Direction Period (s) | S 14 | SSE 9 | ENE 9 | ENE 8 | S 14 | ENE 7 | S 13 | S 13 | S 13 | S 13 | SW 16 | E 8 | E 8 | E 8 | E 7 | SW 16 | NE 7 | NE 7 | NE 7 |
184 | 360 | 754 | 404 | 264 | 222 | 170 | 165 | 119 | 116 | 129 | 86 | 63 | 55 | 39 | 274 | 64 | 62 | 75 | |
Swell 2 Height (m) Direction Period (s) | S 18 | S 13 | SSE 8 | S 7 | S 6 | S 14 | E 9 | SW 17 | SW 18 | SW 18 | S 12 | S 12 | SW 16 | SSW 18 | SSW 17 | NE 7 | SW 17 | SW 16 | SSW 16 |
101 | 115 | 196 | 92 | 35 | 260 | 25 | 74 | 80 | 79 | 44 | 45 | 129 | 207 | 200 | 38 | 295 | 264 | 322 | |
Swell 3 Height (m) Direction Period (s) | W 13 | S 16 | S 13 | S 14 | SW 18 | SSW 6 | SW 6 | W 13 | W 13 | W 12 | NNE 6 | SSW 16 | S 12 | NNE 6 | NNE 6 | E 8 | E 9 | E 8 | S 13 |
30 | 133 | 212 | 250 | 50 | 14 | 8 | 14 | 31 | 25 | 8 | 100 | 45 | 26 | 28 | 28 | 23 | 21 | 54 | |
Wind waves Height (m) Direction Period (s) | E 10 | ENE 9 | SSE 8 | — | ENE 8 | ENE 7 | ENE 7 | ENE 6 | ENE 6 | ENE 9 | E 8 | NNE 6 | NE 6 | — | — | — | — | — | — |
4335 | 1302 | 382 | — | 276 | 148 | 163 | 127 | 98 | 193 | 144 | 26 | 40 | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 219 | 156 | 45 | 1 | 31 | 31 | 1 | 31 | 1 | 1 | 31 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
Best forecast wave conditions in Oahu | |||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||
Header Global | |||||||||||||||||||
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Information about the Number Fours Surf forecast
The above surf forecast table for Number Fours provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Number Fours can be found by selecting the local surf guide option on the grey menu. Our Number Fours 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 (Number Fours) 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 Number Fours 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.
Number Fours is 5 km (3 miles) from Honolulu. If you plan a vacation in Oahu, look for hotels and other accommodation in Honolulu. Honolulu has rooms for a wide range of budgets as well as car hire and transport links.











