Surf Forecasts:
Number Fours surf forecast from 31 Aug 2026:
- Most powerful swell: Saturday 5 Sep, 11AM (local time) - 8ft (2.5m), 14s period, ENE swell with 2,285 kJ wave energy.
Best Forecast Surf Conditions for Number Fours this week:
The most powerful waves expected at Number Fours in the next 16 days are 2.5m 14s and forecast to arrive on Saturday (Sep 05) at 11AM. Winds are predicted to be cross-offshore at the time the swell arrives.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 11AM (Sat 5th Sep) | 8ft (2.5m) 14s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
G’day, Rusty here, your local surf guide. Let’s talk about the next 16 days for Number Fours.
We’re looking at a pretty drawn-out run of onshore, wind-affected swell, with the standout period landing around the 5th to the 7th of September. The water temp is sitting at 81°, which is spot on average for this time of year, so no need to worry about a spring suit just yet.
The forecast kicks off on Monday, 31st August, with a 7ft ENE swell. The wind is a fresh cross-off at 22 mph, which keeps the surface clean, but the wave comment is telling us the conditions are marginal. The combined energy is moderate (640), and the period is short at 7 seconds, so the waves will be a bit lumpy and weak. That theme continues through Tuesday, 1st September, and Wednesday, 2nd September, with the swell holding around 6ft to 7ft, still ENE, and the wind staying fresh. The energy climbs a bit (up to 930) but the period is still short, so it’s not really doing much for us.
Thursday, 3rd September, the swell pushes up to 8ft ENE, and the energy gets into the strong range (1255). Wind is strong at 25 mph, cross-off, so it’s clean but blown out. The size is getting into the intermediate-to-expert territory, but the quality is still poor. Friday, 4th September, the swell hits 10ft in the morning, with strong energy (1640), but it’s the same story – strong wind, marginal conditions. This is getting too big for beginners, and the wind is making it a messy wall for everyone else.
Now, here’s where it gets interesting. Saturday, 5th September, the swell eases a touch to 8ft ENE, but the period jumps to 14 seconds. That’s a proper groundswell, and the energy is very strong (2730). The wind drops to a moderate breeze at 16 mph in the afternoon, still cross-off. This is the best window of the whole run. The water is clean, the swell has real power, and the long period means better shaped waves. Be aware that at Number Fours, which is a reef, this long period energy will produce some nice, orderly lines. It’s still a bit hefty for the less experienced, but for intermediates and up, this is the one to circle. Saturday afternoon looks particularly good.
Sunday, 6th September, holds similar energy (3261) with a 8ft ENE swell and a 13-second period. The wind is fresh again in the morning, but the afternoon is clean. The wave comment is still marginal, so the tide might be a factor, but the power is undeniable.
Then we hit Monday, 7th September. The swell is 8ft ENE, with a 12-second period, and the wind swings to a moderate NNE at 16 mph, going offshore. This is the standout session. The energy is strong (2198), the wind is offshore and clean, and the wave comment says “excellent surf conditions for experienced surfers.” This is a proper reef day with clean, powerful lines. Crowds are possible here, so get in early.
After that, the wheels fall off. Tuesday, 8th September, the swell drops to 3ft, the wind goes onshore, and there’s a risk of thunderstorms. The energy plummets (578). The rest of the week into the 15th of September sees small, weak swells (2ft to 4ft) with fresh to strong cross-off winds, and the energy stays weak (under 400). The period is a mix of short and very long (15 to 18 seconds), but with next to no height, it’s just not worth paddling out. There’s a gap of several days with no real recommendations.
So, to wrap it up: the whole period is a slow burn. The 5th and 6th have the size and power, but Monday, 7th September, is the pick of the lot with clean offshore wind and a solid, long-period swell. Don’t get too excited about the rest of it.
Rusty.
Short Range ForecastMostly dry. Warm (max 27°C on Tue afternoon, min 25°C on Mon morning). Mainly strong winds. | Days 4-6 Weather SummarySome drizzle, heaviest during Sat night. Warm (max 27°C on Sat morning, min 25°C on Thu morning). Mainly strong winds. | ||||||||||||||||||||
Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | |||||||||||||||
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) | ENE 7 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | E 14 | ENE 14 | ENE 13 | ENE 13 | ENE 13 | ENE 12 | ENE 12 |
Wave Graph | |||||||||||||||||||||
405 | 428 | 439 | 475 | 487 | 475 | 439 | 414 | 768 | 828 | 744 | 1145 | 1128 | 727 | 515 | 2285 | 1893 | 2123 | 1808 | 1703 | 1824 | |
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-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 5:48PM0.44m | 7:14AM0.56m | 6:20PM0.36m | 8:21AM0.59m | 6:54PM0.28m | 9:39AM0.62m | 7:57PM0.22m | 10:58AM0.66m | 10:35PM0.19m | 12:05PM0.69m | 00:18AM0.21m | 1:00PM0.73m | 1:21AM0.26m | ||||||||
Low Tide | 12:22PM0.19m | 00:10AM0.05m | 1:40PM0.23m | 00:43AM0.05m | 3:38PM0.25m | 1:25AM0.06m | 6:22PM0.22m | 2:24AM0.08m | 7:30PM0.17m | 3:46AM0.09m | 8:03PM0.13m | 5:11AM0.08m | 8:31PM0.10m | ||||||||
6:13 | — | — | 6:13 | — | — | 6:15 | — | — | 6:15 | — | — | 6:15 | — | — | 6:15 | — | — | 6:16 | — | — | |
— | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:43 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — |
Temp °C | 26 | 26 | 26 | 26 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 26 | 26 | 26 | 27 | 27 | 26 | 27 | 27 | 26 |
Feels °C | 23 | 23 | 24 | 24 | 25 | 24 | 24 | 23 | 24 | 22 | 21 | 21 | 21 | 21 | 24 | 25 | 25 | 26 | 25 | 25 | 25 |
Swell 1 Height (m) Direction Period (s) | SSW 15 | SSW 14 | S 19 | SSW 18 | S 18 | S 17 | S 16 | S 16 | S 15 | S 14 | SSE 13 | SSE 12 | SSE 12 | S 11 | S 11 | S 10 | S 10 | SSW 10 | ENE 13 | SSW 10 | ENE 12 |
144 | 138 | 192 | 333 | 314 | 364 | 422 | 318 | 279 | 206 | 206 | 333 | 494 | 358 | 491 | 367 | 314 | 206 | 1808 | 138 | 1824 | |
Swell 2 Height (m) Direction Period (s) | S 11 | S 11 | S 10 | SSW 14 | S 12 | S 10 | SSE 10 | S 11 | E 13 | SE 13 | S 14 | SSW 14 | SW 12 | E 14 | E 14 | SW 18 | SSW 18 | SSW 16 | SSW 11 | SSW 16 | SSW 18 |
57 | 55 | 50 | 80 | 77 | 35 | 19 | 41 | 123 | 88 | 198 | 61 | 6 | 357 | 515 | 78 | 120 | 102 | 222 | 229 | 340 | |
Swell 3 Height (m) Direction Period (s) | S 21 | SSW 19 | SW 14 | S 10 | SW 14 | SW 14 | SW 14 | E 14 | S 11 | S 10 | E 12 | SW 18 | SW 18 | SW 13 | SSW 20 | NNE 10 | NNE 10 | S 12 | SSW 16 | SSE 12 | SW 10 |
34 | 122 | 54 | 30 | 52 | 51 | 30 | 66 | 38 | 18 | 107 | 12 | 12 | 27 | 38 | 10 | 19 | 46 | 171 | 45 | 102 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 7 | ENE 14 | ENE 13 | ENE 13 | ENE 13 | ENE 12 | — |
405 | 428 | 439 | 475 | 487 | 475 | 439 | 414 | 768 | 828 | 744 | 1145 | 1128 | 727 | 512 | 2285 | 1893 | 2123 | 1060 | 1703 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 46 | 39 | 31 | 32 | 126 | 31 | 39 | 44 | 39 | 127 | 126 | 127 | 48 | 48 | 39 | 31 | 32 | 31 | 39 | 39 | 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.











