Surf Forecasts:
Number Fours surf forecast from 20 Aug 2026:
- Best quality surf: Thursday 20 Aug, 2AM (local time) - 4ft (1.2m), 7s period, ENE swell with cross-offshore winds.
- Most powerful swell: Wednesday 26 Aug, 8PM (local time) - 2.5ft (0.8m), 19s period, S swell with 450 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 2AM (local time) - 4ft (1.2m), 7s 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 Thursday (Aug 20) at 2AM. The primary swell is predicted to be 1.2m and 7s period with a secondary swell of 0.5m and 16s. 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 0.8m 19s and forecast to arrive on Wednesday (Aug 26) at 8PM. 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 6s period and expected on Thursday (Aug 20) at 2AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Thu 20th Aug) | 4ft (1.2m) 7s |
| Best Surf | 2AM (Thu 20th Aug) | 4ft (1.2m) 7s |
| Most Powerful | 8PM (Wed 26th Aug) | 2.5ft (0.8m) 19s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright, Rusty here, let's take a look at what's on the table for Number Fours over the next sixteen days.
It's a bit of a mixed bag, to be honest. We're looking at a real slow start for the first week or so, with mostly onshore winds and messy conditions. The water temp is about average for the time of year, nothing to write home about.
The first real chance of anything decent comes on Thursday the 20th of August. We've got a small but clean 2ft swell from the SSW, with a super long period of 18 seconds. That's proper groundswell energy, and with a light cross-offshore breeze from the ENE, it's going to be glassy. The combined energy is low though, at 261, so it's not going to be packing much punch. Friday the 21st of August morning is a bit cross, but the afternoon cleans right up with glassy conditions and a 2ft SW swell. It's small, but it'll be worth a paddle for the clean lines.
Then the wheels come off. From Saturday the 22nd of August through to the end of the month, the wind cranks up from the ENE. We're talking solid 22 to 28 mph winds, which is just going to wreck the surface. The swell hangs around, but the quality is poor. There's a stretch of days there with nothing good to offer.
The standout for the whole period is actually at the very end, on Monday the 31st of August and Tuesday the 1st of September. The swell jumps up to a solid 8ft to 8ft from the ENE, with a period of 12 to 13 seconds. The combined energy is huge, reading 1986 and 2053, which is very strong. This is a proper swell, but it's big. Over 8ft, it's only for the experts. The wind is still cross-offshore from the ENE, so it'll be clean, but the size will be intimidating. The ENE direction is offshore, which is ideal for the reef here. The water temp is average for the time of year. This is the one to watch, but it's a long way off, so keep an eye on the forecasts.
For the first week, it's a tough call. You're better off waiting for that last week of August and into September. There's a solid window of small but clean surf on the 20th and 21st if you're desperate, but the real heavy stuff is for the experienced crew right at the end of the run.
Rusty.
Short Range ForecastMostly dry. Warm (max 27°C on Thu afternoon, min 25°C on Wed night). Winds increasing (calm on Fri afternoon, strong winds from the ENE by Sat afternoon). | Days 5-7 Weather SummaryLight rain (total 4mm), mostly falling on Mon afternoon. Warm (max 26°C on Sun morning, min 25°C on Sat night). Winds decreasing (strong winds from the ENE on Sun afternoon, moderate winds from the ENE by Mon night). | ||||||||||||||||||
Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | ||||||||||||||
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 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 | SW 16 | SW 16 | E 7 | ENE 7 | ENE 7 | ENE 7 | ENE 6 | ENE 7 | ENE 7 | E 7 | ENE 7 | ENE 7 |
Wave Graph  | |||||||||||||||||||
 kJ | 153 | 207 | 200 | 274 | 291 | 264 | 322 | 261 | 255 | 255 | 316 | 268 | 342 | 280 | 227 | 317 | 329 | 319 | 218 |
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 | 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 |
High Tide | 11:25AM0.56m | 10:11PM0.21m | 12:25PM0.59m | 00:08AM0.21m | 1:12PM0.63m | 1:06AM0.23m | 1:52PM0.66m | 1:46AM0.26m | 2:26PM0.67m | 2:21AM0.29m | 2:56PM0.68m | 2:55AM0.33m | |||||||
Low Tide | 2:47AM0.12m | 8:27PM0.20m | 8:41PM0.17m | 5:06AM0.12m | 9:00PM0.16m | 6:08AM0.10m | 9:18PM0.14m | 6:59AM0.08m | 9:35PM0.13m | 7:43AM0.06m | 9:53PM0.11m | ||||||||
 |  | |  | | | | | | | | | |  |  |  | | | | |
 | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — |
 | 6:58 | — | 6:57 | — | — | 6:57 | — | — | 6:55 | — | — | 6:54 | — | — | 6:53 | — | — | 6:52 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 1 | 2 | — | 3 |
Temp °C | 25 | 26 | 27 | 26 | 27 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 26 | 26 | 26 | 26 |
Feels °C | 25 | 29 | 30 | 29 | 31 | 30 | 29 | 27 | 23 | 23 | 23 | 22 | 22 | 23 | 25 | 26 | 27 | 24 | 26 |
Swell 1 Height (m) Direction Period (s) | ENE 7 | E 8 | ENE 7 | ENE 7 | SW 17 | ENE 7 | ENE 7 | SW 16 | SW 16 | SSW 16 | SW 15 | SSW 15 | SW 14 | SSW 14 | E 8 | SSW 13 | SSW 12 | SSW 16 | SSW 15 |
| kJ | 153 | 54 | 131 | 108 | 291 | 48 | 85 | 261 | 255 | 212 | 115 | 191 | 100 | 166 | 51 | 93 | 86 | 142 | 121 |
Swell 2 Height (m) Direction Period (s) | SW 16 | NE 6 | SSW 17 | SW 16 | NNE 7 | SW 16 | SSW 16 | E 8 | W 11 | S 14 | S 13 | SSE 13 | SSE 13 | SSE 12 | SSW 13 | SSE 11 | SSW 16 | SSW 12 | SSE 10 |
| kJ | 129 | 43 | 200 | 274 | 31 | 264 | 322 | 43 | 62 | 104 | 90 | 34 | 96 | 50 | 156 | 43 | 146 | 56 | 52 |
Swell 3 Height (m) Direction Period (s) | S 12 | SSW 18 | W 11 | W 9 | W 11 | NNE 7 | WNW 10 | W 10 | S 12 | WNW 10 | SSW 15 | S 11 | SSW 15 | SSW 18 | SSE 12 | SSW 17 | SSE 7 | SSE 7 | SSW 12 |
| kJ | 45 | 207 | 37 | 27 | 57 | 26 | 32 | 51 | 47 | 33 | 76 | 22 | 71 | 62 | 48 | 94 | 18 | 9 | 55 |
Wind waves Height (m) Direction Period (s) | NNE 6 | — | — | — | — | — | — | ENE 6 | ENE 6 | E 7 | ENE 7 | ENE 7 | ENE 7 | ENE 6 | ENE 7 | ENE 7 | E 7 | ENE 7 | ENE 7 |
| kJ | 51 | — | — | — | — | — | — | 80 | 207 | 255 | 316 | 268 | 342 | 280 | 227 | 317 | 329 | 319 | 218 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 31 | 42 | 42 | 46 | 127 | 42 | 39 | 39 | 31 | 1 | 31 | 2 |
Best forecast wave conditions in Oahu | |||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||
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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.
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