Surf Forecasts:
Number Fours surf forecast from 19 Aug 2026:
- Best quality surf: Thursday 20 Aug, 5AM (local time) - 1.5ft (0.5m), 17s period, SW swell with cross-offshore winds.
- Most powerful swell: Friday 21 Aug, 11PM (local time) - 2.5ft (0.8m), 16s period, SSW swell with 322 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 5AM (local time) - 1.5ft (0.5m), 17s 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 5AM. The primary swell is predicted to be 0.5m and 17s period with a secondary swell of 0.9m and 8s. Another secondary swell of 0.9m 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 0.8m 16s and forecast to arrive on Friday (Aug 21) 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 1.5m 6s period and expected on Monday (Aug 24) at 11AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5AM (Thu 20th Aug) | 1.5ft (0.5m) 17s |
| Best Surf | 5AM (Thu 20th Aug) | 1.5ft (0.5m) 17s |
| Most Powerful | 11PM (Fri 21st Aug) | 2.5ft (0.8m) 16s |
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 Number Fours has in store for us over the next couple of weeks.
Right off the bat, we're looking at a pretty quiet start. The first few days are going to be small, with waves barely pushing 2ft to 2ft from the SW and SSW. The water temp is sitting at a comfortable 80°, which is right about average for this time of year, so no surprises there. The overall energy is weak, with readings in the low to mid 200s to 300s. While the wind is light and cross-off, giving us clean conditions, the swell just isn't there to get excited about. It's a slow build.
Things start to get a little more interesting around Thursday morning, August 20th, with a clean 2ft SSW swell and a light breeze. The afternoon is even better with glassy, near-calm conditions. Friday, August 21st, is similar, with a clean 2ft SW swell in the afternoon. But honestly, it's still pretty small.
Now, for the standout window. The best we've got is a couple of days around the end of August and into the very start of September. Mark your calendars for the morning of September 1st (Tuesday) and September 2nd (Wednesday). We're looking at a solid 7ft to 7ft swell from the ENE. The period stretches out to 10 to 11 seconds, which means it's got some real groundswell energy behind it. The combined energy readings are massive—hitting over 1000, up to 1534, indicating very strong wave energy. This is the real deal. The wind is offshore, blowing from the ENE at 15 to 19 mph, keeping those faces clean and lined up. This is a setup for a proper session, but at that size, it's definitely expert territory. The swell direction is a solid match for the optimum SSE, coming from the east-northeast, so it'll wrap in nicely.
The pick of the bunch is the morning of Wednesday, September 2nd. That 7ft swell from the east with a 11-second period and moderate offshore breeze is a beautiful thing. But keep in mind this is a long-range call, so it's promising but not set in stone just yet.
Between now and then, there's a lot of small stuff and some strong winds that will keep things messy. The wind cranks up to 25-28 mph from the 23rd through the 25th, making things a write-off. The late August period sees a lot of short-period, windswell that's just not worth paddling out for.
So, to sum it up: it's a slow start, a long gap, and then a promise of some serious surf right at the start of September. Keep an eye on that first week of the new month.
Rusty
Short Range ForecastMostly dry. Warm (max 27°C on Thu morning, min 24°C on Wed morning). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Mon night. Warm (max 27°C on Sat afternoon, min 25°C on Sat night). Mainly strong winds. | ||||||||||||||||||||
Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | |||||||||||||||
AM | 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) | SW 16 | E 8 | ENE 7 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 | SW 16 | SW 16 | ENE 7 | ENE 7 | SSW 15 | ENE 6 | SSW 14 | ENE 6 | ENE 6 | E 8 | ENE 8 | ENE 7 |
Wave Graph | |||||||||||||||||||||
129 | 100 | 153 | 207 | 200 | 274 | 291 | 264 | 322 | 261 | 255 | 261 | 247 | 220 | 172 | 166 | 182 | 153 | 294 | 314 | 210 | |
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-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-off |
High Tide | 10:13AM0.53m | 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 | — | — | 6:11 | — | — | |
— | 6:58 | — | — | 6:57 | — | — | 6:57 | — | — | 6:55 | — | — | 6:54 | — | — | 6:53 | — | — | 6:52 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | 1 | — | 1 |
Temp °C | 25 | 26 | 25 | 27 | 27 | 27 | 26 | 27 | 27 | 26 | 27 | 25 | 26 | 26 | 25 | 26 | 27 | 26 | 26 | 26 | 25 |
Feels °C | 25 | 26 | 25 | 29 | 30 | 31 | 30 | 30 | 30 | 25 | 25 | 23 | 22 | 22 | 22 | 24 | 26 | 26 | 26 | 24 | 23 |
Swell 1 Height (m) Direction Period (s) | E 8 | E 8 | ENE 7 | E 8 | ENE 7 | ENE 7 | ENE 7 | NE 7 | SSW 16 | E 6 | SW 16 | SSW 16 | SSE 13 | SSW 15 | E 9 | SSW 14 | SSW 13 | E 8 | SSW 12 | SSW 16 | SSW 15 |
111 | 84 | 153 | 71 | 127 | 108 | 51 | 67 | 322 | 84 | 255 | 212 | 101 | 191 | 54 | 166 | 156 | 69 | 86 | 142 | 121 | |
Swell 2 Height (m) Direction Period (s) | NNE 7 | S 12 | SW 16 | NE 6 | SSW 17 | SW 16 | SW 17 | SW 16 | W 10 | NE 7 | W 11 | S 14 | SW 15 | SSE 13 | SW 14 | SSE 12 | SSE 12 | SSW 13 | S 16 | SSW 12 | SSW 12 |
30 | 45 | 129 | 42 | 200 | 274 | 291 | 264 | 50 | 54 | 64 | 104 | 115 | 35 | 99 | 50 | 48 | 93 | 131 | 56 | 56 | |
Swell 3 Height (m) Direction Period (s) | SW 16 | SSW 16 | S 12 | SSW 18 | W 11 | W 9 | NNE 7 | W 10 | S 13 | SW 16 | S 12 | WNW 10 | SSW 15 | WNW 10 | SSE 13 | SSW 18 | SSW 18 | SSE 12 | SSE 12 | SSE 11 | SSW 18 |
129 | 100 | 45 | 207 | 37 | 14 | 26 | 52 | 54 | 261 | 47 | 33 | 76 | 21 | 56 | 62 | 31 | 46 | 29 | 43 | 108 | |
Wind waves Height (m) Direction Period (s) | E 8 | NE 6 | NNE 6 | — | — | — | — | — | ENE 7 | — | ENE 7 | ENE 7 | ENE 7 | ENE 6 | ENE 6 | ENE 6 | ENE 6 | ENE 6 | E 8 | ENE 8 | ENE 7 |
48 | 31 | 51 | — | — | — | — | — | 102 | — | 186 | 261 | 247 | 220 | 172 | 150 | 182 | 153 | 294 | 314 | 210 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 1 | 2 | 1 | 0 | 0 | 0 | 13 | 0 | 0 | 39 | 42 | 48 | 47 | 48 | 39 | 39 | 31 | 31 | 31 | 31 | 31 |
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.











