Surf Forecasts:
Number Fours surf forecast from 15 Aug 2026:
- Best quality surf: Thursday 20 Aug, 8PM (local time) - 2ft (0.6m), 17s period, SSW swell with cross-offshore winds.
- Most powerful swell: Sunday 16 Aug, 2AM (local time) - 16ft (5.0m), 10s period, E swell with 5,677 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 8PM (local time) - 2ft (0.6m), 17s period with SSW 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 8PM. The primary swell is predicted to be 0.6m and 17s period with a secondary swell of 0.3m and 11s. Another secondary swell of 1.1m and 7s 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 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 1.0m 8s period and expected on Friday (Aug 21) at 8PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8PM (Thu 20th Aug) | 2ft (0.6m) 17s |
| Best Surf | 8PM (Thu 20th Aug) | 2ft (0.6m) 17s |
| Most Powerful | 2AM (Sun 16th Aug) | 16ft (5.0m) 10s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s on the cards for Number Fours.
Right off the bat, I gotta be honest with you – it’s a tough start. The first few days are a write-off. The wind is howling from the ENE at 31 mph on Saturday, whipping up a 13 ft mess with a combined swell energy of (2667) – that’s powerful but useless. Way too big, way too windy. That’s not surf, that’s a survival session. Sunday isn’t much better, still lumpy and cross-onshore with 8 ft swell, and the rain’s coming down. We’re looking at a solid four-day gap of just poor conditions until things start to settle down.
Finally, by Monday the 17th, the wind eases up to a cross-off breeze from the ENE at 19 mph. The swell drops to a more manageable 5 ft from the ENE, but the period is a short 8 seconds, so it’ll be a bit soft and choppy. Still, it’s clean, and the combined energy is down to (662) – weak to moderate. It’s marginal, but at least you can get wet. The afternoon gets even smaller at 3 ft, but the period stretches out to a long 14 seconds from the south. That’s a bit of a tease – clean, but not a lot of push at this break.
After that, the outlook gets pretty bleak for the rest of the week and into the next. We’re talking tiny waves, 2 ft to 2 ft, for days on end. The winds stay cross-off or light, so it’s clean, but the combined energy is barely breaking (132) to (490) – weak. These are long-period swells from the south and southwest (15-18 seconds), which can be tricky on a reef break if the direction isn’t spot-on. There’s just no power to work with.
Now, here’s where it gets a little interesting. The very end of the forecast window, on Saturday the 30th of August, shows a real pulse of energy. We’re looking at a solid 10 ft swell from the ENE with a decent 14-second period. The combined energy jumps way up to (3591) – strong to very strong wave energy. The wind is a moderate cross-off breeze from the ENE at 16 mph, which should keep it reasonably clean. However, the score is still only a 4 out of 10, so there are some question marks – likely the direction isn't perfect for this reef, or the sheer size could make it unruly. For experts only at that size, but it’s the only real standout in the whole 16-day run.
Keep in mind, the water temp is about what you’d expect for this time of year, no major anomalies to report.
So, to sum it up: a full week and a half of nothing or near-nothing, then a late-summer pulse of big swell at the very end. That Saturday the 30th is your one shot, but it’s a long way out, so treat it as promising but not locked in. Forecasts can change.
Rusty.
Short Range ForecastHeavy rain (total 48mm), heaviest during Sat night. Warm (max 27°C on Sat afternoon, min 24°C on Sat night). Winds decreasing (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 25°C on Mon night). Mainly fresh winds. | ||||||||||||||||||
Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | ||||||||||||||
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 8 | ENE 9 | E 10 | E 10 | ENE 9 | ENE 9 | ENE 8 | ENE 8 | S 14 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | E 8 | SW 16 | SSW 18 | SSW 17 | SW 16 |
Wave Graph | |||||||||||||||||||
952 | 2430 | 3286 | 5677 | 993 | 692 | 449 | 300 | 260 | 173 | 165 | 121 | 143 | 163 | 84 | 129 | 207 | 200 | 274 | |
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-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 |
High Tide | 6:06AM0.44m | 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 | ||||||||
Low Tide | 00:03AM0.04m | 11:43AM0.14m | 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 | ||||||||
— | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | |
7:01 | — | 7:00 | — | — | 7:00 | — | — | 7:00 | — | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | |
mm | — | — | — | 24 | 14 | 8 | 2 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 25 | 26 | 27 | 26 | 26 | 27 | 27 | 26 | 26 | 25 | 25 | 26 | 25 | 25 | 26 | 25 | 26 | 27 | 26 |
Feels °C | 22 | 21 | 22 | 21 | 24 | 27 | 28 | 26 | 26 | 24 | 23 | 24 | 24 | 24 | 26 | 25 | 26 | 28 | 28 |
Swell 1 Height (m) Direction Period (s) | S 14 | S 13 | S 13 | S 14 | SSE 9 | ENE 9 | ENE 8 | S 14 | S 14 | S 13 | S 13 | S 13 | S 13 | ENE 8 | E 8 | E 8 | E 8 | SSW 17 | ENE 7 |
243 | 225 | 168 | 184 | 592 | 692 | 449 | 264 | 260 | 170 | 165 | 119 | 80 | 163 | 84 | 82 | 78 | 200 | 157 | |
Swell 2 Height (m) Direction Period (s) | W 11 | W 11 | S 16 | S 18 | S 16 | SSE 8 | S 7 | S 6 | SSW 6 | SSW 5 | SW 17 | SW 18 | SSE 7 | SW 16 | NE 6 | NE 6 | SSW 18 | S 11 | SW 16 |
9 | 9 | 80 | 56 | 188 | 302 | 92 | 48 | 13 | 5 | 74 | 80 | 15 | 129 | 42 | 34 | 207 | 21 | 274 | |
Swell 3 Height (m) Direction Period (s) | SSW 18 | SW 17 | W 13 | W 13 | SSW 13 | S 10 | S 14 | SW 18 | SSE 6 | W 11 | SW 7 | SSE 8 | SW 18 | S 12 | SSW 12 | SW 16 | S 11 | SSW 8 | S 15 |
30 | 12 | 30 | 30 | 53 | 75 | 250 | 50 | 10 | 10 | 11 | 19 | 79 | 44 | 48 | 129 | 22 | 6 | 38 | |
Wind waves Height (m) Direction Period (s) | ENE 8 | ENE 9 | E 10 | E 10 | ENE 9 | — | — | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | — | — | — | NE 6 | ENE 7 | — |
952 | 2430 | 3286 | 5677 | 993 | — | — | 300 | 231 | 173 | 141 | 121 | 143 | — | — | — | 43 | 121 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 201 | 201 | 201 | 210 | 46 | 45 | 4 | 31 | 2 | 31 | 31 | 31 | 1 | 31 | 1 | 1 | 31 | 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.











