Surf Forecasts:
Number Fours surf forecast from 16 Aug 2026:
- Best quality surf: Monday 17 Aug, 2AM (local time) - 6ft (1.8m), 8s period, ENE swell with cross-offshore winds.
- Most powerful swell: Saturday 15 Aug, 11PM (local time) - 16ft (5.0m), 10s period, E swell with 4,800 kJ wave energy.
- Next surfable swell (1★+): Monday 17 Aug, 2AM (local time) - 6ft (1.8m), 8s period with ENE 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 Monday (Aug 17) at 2AM. The primary swell is predicted to be 1.8m and 8s period with a secondary swell of 0.9m and 7s. Another secondary swell of 1.5m and 8s is also forecast. 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 5.0m 10s and forecast to arrive on Saturday (Aug 15) at 11PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 7s period and expected on Friday (Aug 21) at 5PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Mon 17th Aug) | 6ft (1.8m) 8s |
| Best Surf | 2AM (Mon 17th Aug) | 6ft (1.8m) 8s |
| Most Powerful | 11PM (Sat 15th Aug) | 16ft (5.0m) 10s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright, let’s get into it.
The next couple of weeks at Number Fours are a bit of a mixed bag. We’ve got a solid pulse of energy coming through early on, but it’s going to be messy. Then things back right off before we see a more promising, longer-period swell arriving towards the end of the run. Keep your expectations in check for the first half, and save your energy for the back half of the forecast.
The opening salvos hit Saturday afternoon, the 15th. We’re looking at a solid 15ft of east-northeast swell rolling in with a 10-second period. The energy is strong, with a combined reading of 4073. But the wind is the story – a near-gale from the east-northeast at 34 mph, blowing cross-off. It’s going to be lumpy, bumpy, and pretty wild out there. This is not a day for the faint of heart; more of a "watch from the carpark and wonder" kind of day. The water temp is sitting at 81°, which is about par for the course this time of year.
Sunday the 16th drops down to 8ft, but the period is shorter and there’s a cross-shore breeze and the chance of a thunderstorm. It’s not looking clean, and the energy drops to 1847. Still sizeable, but those conditions are going to make it a battle. The wind eases in the afternoon to 9 mph from the east, and the swell drops a touch to 7ft, but it’s still cross and a bit gutless. One to skip, really.
From Monday the 17th, the bottom falls out. Swell drops to under 3ft, and we’re left with some long-period energy from the south that’s only producing ankle-biters. The period is a long 14 seconds, but there’s just no size to it. This flat spell is going to hang around for the better part of a week. We’ve got clean conditions with the east-northeast cross-off breeze, but there’s nothing to ride. It’s a waiting game.
The pointers start to look a little more interesting from Friday the 21st. We’ve got a small 2ft south-west swell pushing through with a long 17-second period. It’s still small, but the quality is a bit better, and the wind is a light 9 mph. It’s not going to be epic, just a bit of clean fun on the reef. The energy is still weak at 391, but at least it’s something. Saturday the 22nd looks similar, with that south-west groundswell providing the same ankle to knee-high options.
Now, here’s where it gets interesting. After this small, clean window, the wind is set to howl from the east-northeast again from the 24th through the 27th. Swell builds back to 5ft to 7ft, but the periods are short, a junky 6-7 seconds. The energy is moderate, pushing up to 807, but this is all wind-slop and short-period junk. With that strong breeze and the short-period swell, this spot is going to be a mess. Honestly, this looks more like a kite-surfing set-up than a paddling one. Not what we want.
But then, hold on to your boards. The run from Saturday the 29th through to Sunday the 30th has some real potential written all over it. The swell direction swings around to the east with a period that jumps to a very long 16 seconds. The size comes up to 4ft on Saturday morning, building to 5ft by Sunday afternoon. The energy starts to build too, from 1217 up to a strong 1450 by Sunday. The wind on Saturday is a light 6 mph cross-shore, and Sunday it’s a clean 12 mph cross-off. This is the standout window. This is true long-period groundswell – the kind that will wrap into the reef with some proper push and shape. It’s a little way off, so don’t book the time off just yet, but this has the makings of the best waves we’ve seen in the whole forecast. It’s more than a week away, so treat it as promising but keep an eye on it.
So, the plan is simple: sit tight through the junky, blown-out stuff and the flat spell, then be ready for that last weekend of August. That’s where the magic might be.
Rusty
Short Range ForecastHeavy rain (total 44mm), heaviest during Sun morning. Warm (max 27°C on Sat afternoon, min 24°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 27°C on Thu afternoon, min 24°C on Tue night). Wind will be generally light. | |||||||||||||||||||
Sat 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | ||||||||||||||
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) | ENE 10 | E 10 | ENE 9 | ENE 8 | ENE 8 | ENE 8 | S 14 | ENE 7 | ENE 7 | S 13 | ENE 8 | SW 16 | E 8 | SW 16 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 |
Wave Graph | ||||||||||||||||||||
3876 | 2911 | 1057 | 676 | 394 | 264 | 260 | 170 | 165 | 162 | 163 | 147 | 100 | 129 | 207 | 200 | 274 | 291 | 261 | 322 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross | cross | 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-off | cross-off | cross-off |
High Tide | 5:54PM0.53m | 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 | — | 14 | 24 | 5 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 27 | 26 | 25 | 27 | 26 | 26 | 26 | 25 | 25 | 26 | 25 | 26 | 26 | 25 | 26 | 27 | 26 | 26 | 26 | 26 |
Feels °C | 22 | 20 | 23 | 29 | 27 | 26 | 25 | 24 | 24 | 24 | 25 | 26 | 25 | 26 | 27 | 28 | 27 | 28 | 28 | 28 |
Swell 1 Height (m) Direction Period (s) | S 13 | S 14 | SSE 10 | ENE 8 | ENE 8 | S 14 | S 14 | S 13 | S 13 | S 13 | S 13 | SW 16 | E 8 | E 8 | SSW 18 | E 7 | ENE 7 | ENE 7 | NE 7 | ENE 7 |
168 | 179 | 657 | 676 | 394 | 264 | 260 | 170 | 165 | 162 | 116 | 129 | 84 | 82 | 207 | 70 | 77 | 59 | 54 | 70 | |
Swell 2 Height (m) Direction Period (s) | W 13 | S 18 | S 16 | SSE 8 | SSE 7 | S 6 | S 6 | E 9 | SW 17 | SW 18 | SW 18 | S 12 | S 12 | NNE 6 | SSE 11 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 |
30 | 56 | 133 | 223 | 75 | 25 | 16 | 25 | 74 | 80 | 79 | 44 | 71 | 26 | 41 | 200 | 274 | 291 | 261 | 322 | |
Swell 3 Height (m) Direction Period (s) | S 19 | W 13 | W 12 | S 13 | S 14 | SW 18 | SSW 19 | SSW 5 | W 13 | W 13 | W 12 | NE 7 | SSW 16 | SW 16 | SSW 8 | SSE 9 | S 15 | SSE 14 | E 8 | S 13 |
29 | 30 | 25 | 123 | 250 | 50 | 37 | 3 | 14 | 31 | 25 | 8 | 100 | 129 | 6 | 8 | 38 | 41 | 11 | 54 | |
Wind waves Height (m) Direction Period (s) | ENE 10 | E 10 | ENE 9 | — | ENE 8 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 8 | NE 6 | — | ENE 7 | NNE 6 | NNE 6 | — | NNE 7 | — |
3876 | 2911 | 1057 | — | 270 | 244 | 231 | 163 | 163 | 143 | 163 | 147 | 40 | — | 104 | 26 | 16 | — | 29 | — | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 201 | 156 | 58 | 1 | 0 | 31 | 31 | 1 | 31 | 1 | 1 | 31 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 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.











