Surf Forecasts:
Number Fours surf forecast from 7 Sep 2026:
- Best quality surf: Wednesday 9 Sep, 2AM (local time) - 4.5ft (1.3m), 10s period, ENE swell with glassy winds.
- Most powerful swell: Tuesday 8 Sep, 2AM (local time) - 13ft (4.0m), 13s period, SSW swell with 5,172 kJ wave energy.
- Next surfable swell (1★+): Wednesday 9 Sep, 2AM (local time) - 4.5ft (1.3m), 10s 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 Wednesday (Sep 09) at 2AM. The primary swell is predicted to be 0.9m and 14s period with a secondary swell of 1.3m and 10s. Another secondary swell of 1.0m and 8s is also forecast. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Number Fours in the next 16 days are 4.0m 13s and forecast to arrive on Tuesday (Sep 08) at 2AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 10s period and expected on Tuesday (Sep 08) at 2PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Wed 9th Sep) | 4.5ft (1.3m) 10s |
| Best Surf | 2AM (Wed 9th Sep) | 4.5ft (1.3m) 10s |
| Most Powerful | 2AM (Tue 8th Sep) | 13ft (4.0m) 13s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright, Rusty here again. Let’s talk Number Fours. This is a reef break, so it’s got that proper bottom, and it’s fairly consistent. The water is sitting at about 81°F, which is right where you’d expect it for early September – no real surprise there.
We’ve got a long stretch of nothing good upfront. The first chance to get wet is Sunday afternoon the 6th of September, and honestly, it’s pretty marginal. There’s a 6-foot swell from the east-northeast, 12-second period, so it’s got some energy (combined energy around 1761), but the wind is a fresh 19 mph cross-offshore. It’ll be clean on the face, but with thunderstorms threatening, it’s not a lock.
Monday the 7th and Tuesday the 8th are messy. Swells up around 8 to 8 feet with a lot of chop and shifting winds – Tuesday morning even has a southerly onshore blow at 22 mph. The energy is high (touching 2893 on Monday afternoon) but the quality is garbage.
From Wednesday the 9th through the following weekend, the swell drops way off – down to 2 feet or less. There’s some long-period groundswell (up to 22 seconds), but it’s very tiny. A few windows show clean surface conditions with light winds, like Monday afternoon the 14th with a glassy 2-foot groundswell, or Tuesday the 15th with similar tiny but clean 2-foot waves. It’s surfable, but barely.
The best bet in this whole 16-day window is Friday the 18th of September. Early morning, it’s glassy with a very light easterly, a 2-foot, 17-second SSW groundswell with okay energy (537). It’s small, but the surface will be clean. Saturday the 19th and Sunday the 20th also offer glassy conditions, with a 3-foot SSW swell at 15 seconds and almost no wind. That’s when you’ll want to be out there for a quiet, mellow session. The energy is moderate, in the 400-500 range.
So, there’s a long dry spell until around the 14th, and the real standouts are the 18th, 19th, and 20th of September. Expect crowds to be possible at Number Fours when it gets clean. For now, it’s a waiting game.
Rusty.
Short Range ForecastHeavy rain (total 39mm), heaviest during Sun night. Warm (max 28°C on Tue afternoon, min 24°C on Sun night). Winds decreasing (strong winds from the SSE on Mon night, calm by Tue night). | Days 5-7 Weather SummaryLight rain (total 2mm), mostly falling on Wed afternoon. Warm (max 27°C on Wed afternoon, min 24°C on Fri night). Winds decreasing (fresh winds from the ENE on Thu morning, light winds from the ESE by Sat morning). | |||||||||||||||||||
Sun 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | ||||||||||||||
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) | ENE 12 | ENE 12 | ENE 12 | ENE 12 | SSW 13 | S 10 | ENE 11 | ENE 10 | SSW 14 | SSW 13 | SSW 13 | ENE 7 | ENE 7 | SW 16 | SW 16 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 |
Wave Graph  | ||||||||||||||||||||
 kJ | 1064 | 1338 | 1703 | 1461 | 5172 | 861 | 638 | 356 | 269 | 257 | 203 | 231 | 203 | 214 | 206 | 308 | 379 | 255 | 209 | 135 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross | cross | cross | cross-on | on | on | glassy | cross | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-on | cross-on | cross |
High Tide | 1:21AM0.26m | 1:47PM0.73m | 2:09AM0.32m | 2:28PM0.72m | 2:51AM0.39m | 3:05PM0.69m | 3:32AM0.45m | 3:39PM0.64m | 4:11AM0.50m | 4:12PM0.57m | 4:51AM0.54m | 4:42PM0.50m | ||||||||
Low Tide | 8:31PM0.10m | 6:25AM0.07m | 8:57PM0.08m | 7:26AM0.06m | 9:22PM0.06m | 8:21AM0.06m | 9:46PM0.05m | 9:12AM0.07m | 10:10PM0.04m | 10:02AM0.10m | 10:33PM0.04m | 10:52AM0.13m | 10:56PM0.05m | |||||||
 |  | | | |  |  | | | |  |  | |  | | | | | | | |
 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — |
 | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:37 | — |
mm | 3 | 14 | 5 | 4 | 9 | 3 | — | 1 | — | 1 | 1 | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 26 | 26 | 27 | 27 | 27 | 28 | 27 | 27 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 26 |
Feels °C | 26 | 27 | 24 | 27 | 26 | 26 | 29 | 31 | 31 | 29 | 27 | 24 | 25 | 24 | 24 | 24 | 24 | 29 | 28 | 29 |
Swell 1 Height (m) Direction Period (s) | ENE 12 | ENE 12 | SW 12 | ENE 12 | SSW 13 | ENE 11 | SSW 8 | ENE 10 | ENE 9 | ENE 8 | SSW 13 | E 12 | E 12 | SW 16 | ENE 7 | ENE 11 | ENE 11 | SW 15 | ENE 10 | ENE 10 |
| kJ | 1064 | 1338 | 497 | 1461 | 4001 | 785 | 380 | 339 | 186 | 176 | 195 | 141 | 101 | 214 | 151 | 308 | 379 | 242 | 209 | 135 |
Swell 2 Height (m) Direction Period (s) | SSW 12 | SSW 14 | SSW 17 | SW 12 | ENE 12 | WSW 10 | ENE 11 | SSW 8 | SSW 14 | SSW 13 | E 13 | SSW 13 | SSW 13 | E 11 | SW 16 | SW 15 | SW 15 | NNE 8 | NNE 9 | NE 9 |
| kJ | 517 | 1048 | 498 | 678 | 1211 | 586 | 638 | 123 | 269 | 257 | 156 | 131 | 93 | 91 | 206 | 229 | 226 | 45 | 49 | 75 |
Swell 3 Height (m) Direction Period (s) | S 19 | S 18 | SSE 7 | SSW 16 | SSW 15 | SSW 15 | W 9 | SSW 14 | E 13 | E 13 | S 7 | SW 16 | SW 18 | SW 11 | E 11 | NNE 8 | SW 9 | SW 8 | SSW 16 | SSW 13 |
| kJ | 180 | 243 | 69 | 582 | 581 | 468 | 220 | 356 | 219 | 166 | 24 | 133 | 155 | 71 | 89 | 50 | 27 | 11 | 99 | 68 |
Wind waves Height (m) Direction Period (s) | — | — | ENE 12 | ENE 7 | SSW 13 | S 10 | — | — | — | — | ENE 7 | ENE 7 | ENE 7 | ENE 7 | — | — | — | ENE 10 | — | — |
| kJ | — | — | 1703 | 172 | 5172 | 861 | — | — | — | — | 203 | 231 | 203 | 173 | — | — | — | 255 | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 39 | 1 | 147 | 58 | 79 | 126 | 19 | 0 | 1 | 1 | 1 | 31 | 1 | 2 | 31 | 31 | 1 | 1 | 13 | 1 |
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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