
Surf Forecasts:
Number Fours surf forecast from 11 Aug 2026:
- Most powerful swell: Sunday 16 Aug, 8PM (local time) - 8ft (2.5m), 11s period, ENE swell with 1,615 kJ wave energy.
Best Forecast Surf Conditions for Number Fours this week:
The most powerful waves expected at Number Fours in the next 16 days are 2.5m 11s and forecast to arrive on Sunday (Aug 16) at 8PM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 12s period and expected on Thursday (Aug 13) at 5AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 8PM (Sun 16th Aug) | 8ft (2.5m) 11s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright crew, Rusty here. Let’s talk about Number Fours and what’s coming down the pike for the next couple of weeks. It’s a bit of a grind, honestly, so keep your expectations in check.
The main story is a steady cross-off wind from the ENE that keeps the surface clean, but the wave quality is mostly poor or just barely surfable. The combined swell energy is moderate to strong, ranging from 425 to 2429, but the direction and period are all over the place. The first real chance to paddle out is on Tuesday, August 11th, but it’s a tough start.
Tuesday morning, August 11th, we’ve got a 4.6ft swell from the ENE, but it’s got a short period of 7 seconds, and the combined energy is just 425. The wind is a fresh 30 km/h cross-off, so it’s clean, but the conditions are poor. Not worth the effort. Tuesday afternoon the swell drops to 2.6ft from the SSW, with a much longer 14-second period, and energy climbs to 520. It’s still marginal, and the tide might be a factor.
Wednesday, August 12th, through Thursday, August 13th, the swell sits around 3.0ft to 3.3ft from the S and SSE, with periods of 16 to 18 seconds – that’s proper groundswell. The energy is up there, around 876 to 944, and the wind is still a clean cross-off. But it’s all marginal. For a reef like Number Fours, that long period groundswell should wrap in, but the size is just too small to get excited.
The end of the first week, Friday, August 14th, the morning is similar, 3.3ft S swell at 14 seconds, but then the afternoon turns into a messy 6.2ft from the ENE. That’s a poor shift. Saturday, August 15th, and Sunday, August 16th, see the swell build to 6.6ft to 8.2ft from the ENE, with periods of 9 to 11 seconds. The energy spikes to 1790 by Sunday afternoon. The wind cranks up to 40 to 45 km/h cross-off – it’s clean, but the wave quality is marginal. For a reef, that 8.2ft Sunday afternoon could be a rowdy one for the experienced crowd. It’s the best of a bad bunch in the first week, but not a standout.
Then we hit a rough patch. Monday, August 17th, the wind swings to a strong cross-on from the SE and SSE, up to 40 km/h, with thunderstorm risk. The swell is 7.9ft from the ENE, but the energy is a massive 2429. The conditions are poor, with a strong cross-onshore mess. This is more of a kite-surfing setup. Through Tuesday, August 18th, to Friday, August 21st, it’s a mix of tiny, short-period junk and weak groundswell. The wind stays cross-off, but the energy drops to the 200 to 500 range. It’s a write-off.
Now, here’s the one true standout. Look at Thursday, August 20th, afternoon. The swell is only 2.0ft, but it’s from the SSW at a very long 18 seconds. The energy is 543. The wind is a clean 20 km/h cross-off. The score is a 2 out of 10, which is the highest we see for a long time. For a reef like Number Fours, which is a bit inconsistent, a tiny, long-period, glassy groundswell can be a gem. The water is about average for the time of year. This is the one to circle. The crowds are sometimes a thing here, so on a tiny, clean day like this, you might have it to yourself. It’s the best on offer.
The second week, from Saturday, August 22nd, to Wednesday, August 26th, is a bit of a blur. Saturday the 22nd has a 5.2ft to 5.9ft ENE short-period swell with clean cross-off wind, but it’s marginal. Sunday, August 23rd, sees a 3.3ft SSW groundswell at 15 seconds, with 1063 energy, scoring a 2 – that’s another promising but small window. The last few days, from Monday the 24th to Wednesday the 26th, are a mix of ENE short-period junk and small S/SSW groundswells in the 2.3ft to 3.3ft range, with periods of 14 to 16 seconds. The wind stays cross-off. The energy is moderate to strong (672 to 1135). It’s all marginal, but the Wednesday the 26th morning session, with a 3.3ft S swell at 15 seconds and 1135 energy, and a clean cross-off, could be a sneaky little window.
The bottom line: the best day to be in the water is Thursday, August 20th, afternoon. It’s a tiny, clean, long-period groundswell that’s actually decent for this stretch. After that, Sunday
Short Range ForecastMostly dry. Warm (max 27°C on Tue morning, min 25°C on Tue night). Mainly fresh winds. | Days 5-7 Weather SummarySome drizzle, heaviest during Sun afternoon. Warm (max 26°C on Thu night, min 25°C on Thu night). Mainly strong winds. | ||||||||||||||||||
Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | ||||||||||||||
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 7 | ENE 7 | SSW 14 | S 20 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 | S 14 | ENE 8 | ENE 8 | ENE 9 | ENE 9 | ENE 11 | ENE 11 | ENE 11 | ENE 11 |
Wave Graph | |||||||||||||||||||
186 | 203 | 269 | 276 | 509 | 498 | 520 | 501 | 662 | 537 | 416 | 395 | 589 | 603 | 764 | 1485 | 1429 | 1503 | 1576 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | 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 | cross-off | cross-off | cross-off |
High Tide | 2:55AM0.26m | 3:35PM0.79m | 3:43AM0.31m | 4:13PM0.75m | 4:30AM0.36m | 4:48PM0.69m | 5:17AM0.40m | 5:22PM0.62m | 6:06AM0.44m | 5:54PM0.53m | 6:57AM0.47m | 6:24PM0.45m | |||||||
Low Tide | 10:10PM0.06m | 8:15AM-0.02m | 10:40PM0.05m | 9:08AM-0.00m | 11:08PM0.04m | 9:58AM0.03m | 11:36PM0.04m | 10:49AM0.08m | 00:03AM0.04m | 11:43AM0.14m | 00:30AM0.05m | 12:43PM0.20m | 00:58AM0.06m | ||||||
— | 6:07 | — | — | 6:07 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | |
7:05 | — | 7:04 | — | — | 7:02 | — | — | 7:02 | — | — | 7:01 | — | — | 7:00 | — | — | 7:00 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 38 |
Temp °C | 26 | 27 | 27 | 25 | 26 | 26 | 25 | 26 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 |
Feels °C | 26 | 26 | 25 | 23 | 24 | 24 | 23 | 24 | 24 | 24 | 23 | 22 | 24 | 24 | 23 | 24 | 23 | 23 | 23 |
Swell 1 Height (m) Direction Period (s) | SSW 15 | SSW 14 | SSW 14 | SSW 14 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 | S 14 | S 14 | S 14 | S 13 | S 13 | S 13 | S 13 | S 13 | S 14 |
186 | 165 | 269 | 243 | 509 | 498 | 520 | 501 | 662 | 537 | 416 | 333 | 306 | 222 | 168 | 222 | 116 | 160 | 188 | |
Swell 2 Height (m) Direction Period (s) | SSE 9 | SSW 11 | SSE 9 | S 20 | SSW 13 | SSW 13 | SSW 13 | SSW 12 | W 12 | W 11 | W 12 | W 12 | W 11 | W 11 | E 11 | S 18 | S 16 | S 16 | S 16 |
17 | 41 | 16 | 276 | 218 | 218 | 170 | 150 | 11 | 10 | 11 | 11 | 9 | 9 | 91 | 56 | 132 | 127 | 81 | |
Swell 3 Height (m) Direction Period (s) | SSW 11 | SSE 9 | S 21 | SSE 8 | W 13 | W 12 | W 12 | W 12 | SW 19 | SW 18 | SW 18 | SSW 18 | SSW 17 | NNW 9 | W 13 | W 13 | W 12 | W 12 | W 11 |
23 | 16 | 79 | 14 | 30 | 25 | 25 | 11 | 14 | 13 | 12 | 30 | 29 | 8 | 30 | 30 | 25 | 25 | 22 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 6 | ENE 6 | E 7 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 8 | ENE 9 | ENE 9 | ENE 11 | ENE 11 | ENE 11 | ENE 11 |
186 | 203 | 156 | 191 | 182 | 172 | 270 | 225 | 268 | 326 | 403 | 395 | 589 | 603 | 764 | 1485 | 1429 | 1503 | 1576 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 1 | 31 | 32 | 31 | 31 | 33 | 31 | 34 | 44 | 32 | 39 | 126 | 31 | 127 | 201 | 31 | 201 | 201 | 147 |
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.











