Surf Forecasts:
Number Fours surf forecast from 18 Aug 2026:
- Best quality surf: Thursday 20 Aug, 2AM (local time) - 1.5ft (0.5m), 16s period, SW swell with cross-offshore winds.
- Most powerful swell: Tuesday 25 Aug, 2AM (local time) - 8ft (2.4m), 8s period, ENE swell with 678 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 2AM (local time) - 1.5ft (0.5m), 16s 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 2AM. The primary swell is predicted to be 0.5m and 16s period with a secondary swell of 0.9m 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 8s and forecast to arrive on Tuesday (Aug 25) 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 7s period and expected on Thursday (Aug 20) at 11PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Thu 20th Aug) | 1.5ft (0.5m) 16s |
| Best Surf | 2AM (Thu 20th Aug) | 1.5ft (0.5m) 16s |
| Most Powerful | 2AM (Tue 25th Aug) | 8ft (2.4m) 8s |
Table - best surf conditions forecast for Number Fours over the next 16 days.
The Lowdown
Alright, let’s take a look at Number Fours, a reef break that’s exposed to the swell and has a best direction from the SSE. Right now, the water’s sitting at a warm 81°, which is about average for this time of year, so no surprises there.
The next 16 days are a bit of a mixed bag, and honestly, the first week is pretty grim. We’ve got small, weak swells mixed with strong, gusty cross-offshore winds that are going to make it tough to find anything worth paddling out for. The early part of the window is a write-off for any decent surf.
There’s a real lull through the middle of the week, with nothing surfable until things start to shift around the end of the month. The standout window is shaping up for the final weekend of August and into the start of September.
Let’s talk about the best on offer. Saturday, the 29th of August, afternoon looks like the brightest spot. We’re seeing a clean 8 ft swell from the ENE, with a period of 8 seconds, and the wind drops to a gentle 9 mph breeze. The combined wave energy is strong at 962. This is a proper, powerful swell that’s going to be pushing through, but at this size, it’s for experienced surfers only. The wind is light and cross-offshore, which should keep the faces clean and lined up. Even though the period is a bit on the short side, the sheer size and energy will make for some solid, punchy reef waves. Expect crowds to be possible here, as it’s a known spot.
After that, Sunday the 30th of August afternoon sees the swell jump to 10 ft from the ENE, with a combined energy of 1886, making it a very strong, powerful swell. The wind remains moderate, but this is big, serious, expert-only territory. The period is still short, so it’ll be a bit walled up and take some real nerve to handle.
Looking further ahead into the first few days of September, the swell drops back a bit, but the energy stays high, and the period stretches out to 10 seconds, which should improve the shape. The wind stays cross-offshore, but it’s a longer-range call, so treat it as promising but not locked in.
Overall, if you’re an experienced surfer, the weekend of the 29th and 30th of August is where you want to focus. The rest of the time is either too small, too windy, or too messy for a proper session.
Rusty.
Short Range ForecastMostly dry. Warm (max 27°C on Thu afternoon, min 24°C on Tue night). Winds decreasing (fresh winds from the ENE on Tue afternoon, calm by Thu night). | Days 4-6 Weather SummaryMostly dry. Warm (max 27°C on Fri afternoon, min 25°C on Fri morning). Winds increasing (calm on Fri afternoon, strong winds from the ENE by Sun morning). | ||||||||||||||||||||
Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | |||||||||||||||
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 | E 8 | ENE 8 | SW 16 | E 8 | SW 16 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | SSW 16 | SW 16 | SW 16 | E 7 | E 7 | E 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 |
Wave Graph | |||||||||||||||||||||
165 | 120 | 155 | 129 | 100 | 129 | 207 | 200 | 274 | 291 | 261 | 322 | 261 | 255 | 428 | 569 | 439 | 350 | 435 | 456 | 678 | |
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 | glassy | cross-on | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 2:26PM0.67m | 2:21AM0.29m | ||||||||
Low Tide | 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 | 6:59AM0.08m | 9:35PM0.13m | ||||||||||
6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | |
— | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:57 | — | — | 6:55 | — | — | 6:54 | — | — | 6:53 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 25 | 26 | 25 | 25 | 26 | 25 | 26 | 27 | 26 | 26 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 26 | 26 | 25 |
Feels °C | 23 | 23 | 24 | 25 | 25 | 26 | 27 | 29 | 29 | 29 | 30 | 28 | 26 | 23 | 24 | 23 | 23 | 22 | 23 | 23 | 23 |
Swell 1 Height (m) Direction Period (s) | S 13 | E 8 | S 13 | E 8 | E 8 | E 8 | E 8 | ENE 7 | NE 7 | ENE 7 | ENE 7 | SSW 16 | SW 16 | SW 16 | SSW 16 | SSE 13 | SSW 15 | SSE 13 | SSE 12 | SSE 11 | SSE 10 |
165 | 120 | 116 | 86 | 84 | 102 | 72 | 134 | 82 | 67 | 96 | 322 | 261 | 255 | 212 | 99 | 144 | 139 | 169 | 148 | 77 | |
Swell 2 Height (m) Direction Period (s) | SW 17 | S 13 | SW 18 | SW 16 | S 12 | SW 16 | SSW 18 | SSW 17 | SW 16 | SW 17 | SW 16 | WNW 10 | E 8 | WNW 10 | S 14 | SW 15 | SE 13 | SE 11 | SSW 14 | SSW 13 | SSW 13 |
74 | 119 | 79 | 129 | 45 | 129 | 207 | 200 | 274 | 291 | 261 | 32 | 33 | 35 | 104 | 116 | 88 | 61 | 127 | 102 | 127 | |
Swell 3 Height (m) Direction Period (s) | E 9 | SW 18 | W 12 | S 12 | SSW 16 | S 12 | S 11 | S 11 | E 8 | NNE 6 | W 10 | S 13 | WNW 10 | S 12 | WNW 11 | SSW 15 | WNW 11 | SW 14 | SSW 18 | SSW 18 | SSW 17 |
15 | 80 | 25 | 44 | 100 | 45 | 23 | 21 | 31 | 28 | 51 | 54 | 34 | 47 | 40 | 76 | 12 | 100 | 31 | 31 | 55 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | NNE 7 | ENE 8 | NE 6 | NNE 6 | NE 6 | NNE 6 | — | — | — | — | ENE 7 | ENE 6 | ENE 6 | E 7 | E 7 | E 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 |
163 | 34 | 155 | 43 | 26 | 34 | 26 | — | — | — | — | 102 | 107 | 226 | 428 | 569 | 439 | 350 | 435 | 456 | 678 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 1 | 1 | 1 | 1 | 0 | 7 | 0 | 0 | 13 | 1 | 31 | 31 | 39 | 39 | 42 | 44 | 31 | 39 | 39 | 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.











