Surf Forecasts:
Number Fours surf forecast from 18 Aug 2026:
- Best quality surf: Wednesday 19 Aug, 8PM (local time) - 1.5ft (0.4m), 16s period, SSW swell with cross-offshore winds.
- Most powerful swell: Monday 24 Aug, 8PM (local time) - 8ft (2.4m), 7s period, ENE swell with 604 kJ wave energy.
- Next surfable swell (1★+): Wednesday 19 Aug, 8PM (local time) - 1.5ft (0.4m), 16s 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 Wednesday (Aug 19) at 8PM. The primary swell is predicted to be 0.4m and 16s period with a secondary swell of 0.8m and 8s. 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 2.4m 7s and forecast to arrive on Monday (Aug 24) 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 0.9m 7s period and expected on Friday (Aug 21) at 5AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8PM (Wed 19th Aug) | 1.5ft (0.4m) 16s |
| Best Surf | 8PM (Wed 19th Aug) | 1.5ft (0.4m) 16s |
| Most Powerful | 8PM (Mon 24th Aug) | 8ft (2.4m) 7s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
G’day, Rusty here. Alright, let’s have a proper look at what’s on the cards for Number Fours.
Right off the bat, the first week or so is a bit of a struggle. We’ve got some swell around, but it’s mostly small and the wind, while cross-offshore, is a persistent moderate breeze that’s keeping things from coming together nicely. The water temp is sitting at a comfortable 81°, which is pretty normal for this time of year.
The first real glimmer of hope shows up on Thursday, the 20th of August. The morning and afternoon both have a clean 2 ft swell from the SSW with a very long period of 17-18 seconds. That’s groundswell energy, and with a light breeze onshore, it’s going to be glassy and clean. The combined swell energy is moderate (322). It’s not big, but for a reef break like Number Fours, that long period and clean surface will make for some fun, lined-up waves. This is the standout of the first week – a sneaky good session for the intermediate surfer who’s paying attention.
After that, it gets a bit messy. Friday the 21st sees the wind shift to a light cross-shore, which will put some small ripples on the face, and the swell drops off again. The weekend of the 22nd and 23rd is a write-off. The wind picks up to a fresh breeze, and on Sunday the 23rd the swell jumps to 6 ft, but it’s a short-period, wind-affected mess from the ENE, giving poor conditions.
Then we hit a long, frustrating stretch. From Monday the 24th all the way through to the end of the month, the swell gets bigger – up to 10 ft by the 28th – but it’s all short-period (7-9 seconds) ENE windswell with a strong to very strong combined energy (up to 1890). The wind stays cross-off but it’s a fresh to strong breeze the whole time. That much short-period energy with that much wind is going to be a churning, bumpy mess. Honestly, that setup looks far more interesting for kite surfing than paddle surfing – it’s going to be blown-out and unruly for a standard board.
The only other small window to keep an eye on is Thursday the 27th and Friday the 28th. The swell hits 10 ft with a period stretching to 9 seconds and energy is very high. It’s marginal at best for paddle surfing given the fresh wind, but if you’re an expert with a lot of patience, it could be a wild, challenging session. For most of us, it’s a skip.
So, bottom line: the best of the lot is that Thursday the 20th. Get out there for the morning or afternoon glass-off. After that, it’s a long, windy gap of poor to marginal conditions until the very end of the forecast period. The break is fairly consistent, so things could change, but right now, it’s a waiting game.
Rusty.
Short Range ForecastMostly dry. Warm (max 26°C on Mon afternoon, min 24°C on Mon night). Mainly fresh winds. | Days 5-7 Weather SummaryMostly dry. Warm (max 27°C on Thu afternoon, min 24°C on Thu night). Winds increasing (light winds from the NE on Thu night, fresh winds from the ENE by Sun morning). | |||||||||||||||||||
Mon 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | ||||||||||||||
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) | S 14 | ENE 7 | S 13 | S 13 | ENE 8 | SW 16 | E 8 | SW 16 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 | SW 16 | SW 16 | ENE 7 | ENE 7 | ENE 6 | ENE 7 |
Wave Graph | ||||||||||||||||||||
260 | 172 | 165 | 136 | 159 | 129 | 100 | 129 | 207 | 200 | 274 | 291 | 261 | 322 | 261 | 255 | 307 | 265 | 207 | 295 | |
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 | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 6:52PM0.37m | 8:59AM0.51m | 7:16PM0.30m | 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 | ||||||||
Low Tide | 1:27AM0.08m | 3:56PM0.27m | 2:01AM0.10m | 2:47AM0.12m | 8:27PM0.20m | 8:41PM0.17m | 5:06AM0.12m | 9:00PM0.16m | 6:08AM0.10m | 9:18PM0.14m | ||||||||||
— | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | |
7:00 | — | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:57 | — | — | 6:55 | — | — | 6:54 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 25 | 25 | 26 | 25 | 25 | 26 | 25 | 26 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 26 | 26 | 25 |
Feels °C | 26 | 24 | 24 | 23 | 24 | 25 | 27 | 26 | 27 | 29 | 29 | 28 | 28 | 28 | 26 | 24 | 24 | 24 | 24 | 23 |
Swell 1 Height (m) Direction Period (s) | ENE 7 | S 13 | ENE 7 | S 13 | S 13 | E 8 | E 8 | E 8 | E 8 | ENE 7 | ENE 7 | SW 17 | NE 7 | ENE 7 | SW 16 | SW 16 | SSW 16 | S 13 | SSW 15 | SW 14 |
237 | 170 | 135 | 119 | 116 | 109 | 84 | 63 | 72 | 101 | 108 | 291 | 65 | 85 | 261 | 255 | 212 | 90 | 144 | 100 | |
Swell 2 Height (m) Direction Period (s) | S 14 | E 9 | S 13 | SW 18 | SW 18 | NNE 7 | SSW 16 | NE 6 | SSW 18 | SSW 17 | SW 16 | E 7 | SW 16 | SSW 16 | E 8 | ESE 8 | S 14 | SW 15 | SSE 11 | SSE 13 |
260 | 25 | 165 | 80 | 79 | 30 | 100 | 31 | 207 | 200 | 274 | 36 | 261 | 322 | 29 | 22 | 104 | 115 | 24 | 57 | |
Swell 3 Height (m) Direction Period (s) | SSE 5 | SW 6 | SW 17 | W 13 | W 12 | SW 16 | S 12 | SW 16 | NNE 6 | S 11 | S 11 | NNE 7 | W 10 | WNW 10 | WNW 10 | WNW 10 | WNW 10 | WNW 11 | WNW 11 | SSW 15 |
6 | 6 | 74 | 31 | 25 | 129 | 45 | 129 | 27 | 21 | 21 | 30 | 33 | 32 | 33 | 35 | 19 | 47 | 22 | 71 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | — | ENE 7 | ENE 8 | — | NE 6 | — | — | — | — | — | — | — | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 6 | ENE 7 |
153 | 172 | — | 136 | 159 | — | 31 | — | — | — | — | — | — | — | 80 | 125 | 307 | 265 | 207 | 295 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 2 | 2 | 31 | 31 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 31 | 32 | 31 | 126 | 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.











