Surf Forecasts:
Nanakuli Blackrocks surf forecast from 28 Aug 2026:
- Best quality surf: Friday 28 Aug, 5AM (local time) - 3.5ft (1.1m), 16s period, S swell with offshore winds.
- Most powerful swell: Friday 28 Aug, 5AM (local time) - 3.5ft (1.1m), 16s period, S swell with 570 kJ wave energy.
- Next surfable swell (1★+): Friday 28 Aug, 5AM (local time) - 3.5ft (1.1m), 16s period with S swell.
Best Forecast Surf Conditions for Nanakuli Blackrocks this week:
The surf forecast for Nanakuli Blackrocks over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Friday (Aug 28) at 5AM. The primary swell is predicted to be 1.1m and 16s period with a secondary swell of 0.4m and 11s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Nanakuli Blackrocks in the next 16 days are 1.1m 16s and forecast to arrive on Friday (Aug 28) at 5AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.7m 6s period and expected on Sunday (Aug 30) at 2PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5AM (Fri 28th Aug) | 3.5ft (1.1m) 16s |
| Best Surf | 5AM (Fri 28th Aug) | 3.5ft (1.1m) 16s |
| Most Powerful | 5AM (Fri 28th Aug) | 3.5ft (1.1m) 16s |
Table - best surf conditions forecast for Nanakuli Blackrocks over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s talk about what we’ve got brewing at Nanakuli Blackrocks.
First up, this spot is a tricky one—it rarely breaks, so when it does line up, you’ve gotta be on it. The water temp is about average for this time of year, nothing wild to report there.
The pattern kicks off on Friday the 28th of August with a clean, moderate offshore wind out of the ENE. Swell is coming in from the S at 3ft, period 14 seconds, with combined energy in the moderate range (369). That’s a solid little groundswell pulse, but the long period means the shape might be better off on a point or reef. Still, for a spot that rarely shows, Friday morning is a decent shout.
Saturday and Sunday drop off a touch in size—3ft to 2ft—with the wind staying offshore but picking up a bit, especially Saturday afternoon with that fresh breeze. Sunday morning cleans up with a longer 16-second SSW swell, energy at 317, but the size is small.
We get a bit of a lull through the first few days of September, with waves hovering around 2ft to 3ft. The standout window looks like Wednesday the 2nd of September into Thursday the 3rd. On Wednesday morning, we’ve got 3ft from the S, period 16 seconds, combined energy 473, and a moderate offshore breeze. That’s good surf conditions, clean lines. Thursday keeps it tidy with a gentle offshore and 3ft, 14-second swell.
Now, the real highlight—the one worth circling—is Sunday the 6th of September into Monday the 7th. Sunday afternoon goes glassy, with a 3ft SSW swell, period 17 seconds, and energy jumping to 563. That’s very good surf conditions. Then Monday morning hits with 4ft from the SSW, period 16 seconds, combined energy 763—strong wave energy—and glassy conditions out of the NNW. That’s the pick of the run. The swell direction lines up well for Blackrocks. Just keep in mind, this spot is inconsistent and crowds can be an issue when it’s on.
After that, Tuesday the 8th still holds clean 4ft surf with light offshore wind, energy at 621. Things taper off into the second week, with smaller glassy waves in the 2ft to 3ft range through to the 12th of September. The last few days are tiny, low energy, and not worth the paddle unless you’re desperate.
Bottom line: don’t sleep on that Sunday 6th to Monday 7th window. That’s the one that’s got me excited.
Rusty.
Short Range ForecastMostly dry. Warm (max 28°C on Fri afternoon, min 25°C on Thu night). Mainly fresh winds. | Days 5-7 Weather SummaryMostly dry. Warm (max 29°C on Tue afternoon, min 25°C on Sun night). Wind will be generally light. | ||||||||||||||||||
Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | ||||||||||||||
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 16 | S 14 | S 14 | S 13 | S 13 | S 13 | SSW 17 | SSW 16 | SSW 16 | SSW 15 | SSW 15 | SSW 14 | S 19 | SSW 18 | S 18 | S 17 | S 16 | S 16 | S 15 |
Wave Graph  | |||||||||||||||||||
 kJ | 582 | 329 | 399 | 225 | 215 | 215 | 186 | 223 | 160 | 199 | 191 | 180 | 273 | 329 | 314 | 459 | 422 | 401 | 275 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | off | off | off | off | off | off | off | off | off | off | off | off | off | off | off | off | off | off |
High Tide | 3:54AM0.41m | 4:06PM0.63m | 4:33AM0.46m | 4:30PM0.57m | 5:15AM0.50m | 4:54PM0.51m | 6:01AM0.54m | 5:16PM0.44m | 6:54AM0.57m | 5:35PM0.37m | 8:00AM0.58m | 5:33PM0.31m | |||||||
Low Tide | 10:23PM0.11m | 9:29AM0.11m | 10:41PM0.10m | 10:14AM0.14m | 11:00PM0.09m | 11:03AM0.19m | 11:21PM0.08m | 12:00PM0.24m | 11:44PM0.07m | 1:15PM0.28m | 00:13AM0.07m | 3:27PM0.30m | 00:49AM0.08m | ||||||
 |  | | |  | |  | | | | | | | | | | | | | |
 | — | 6:13 | — | — | 6:15 | — | — | 6:15 | — | — | 6:15 | — | — | 6:15 | — | — | 6:16 | — | — |
 | 6:52 | — | 6:52 | — | — | 6:51 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | — | 6:47 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 25 | 27 | 28 | 25 | 27 | 28 | 26 | 27 | 27 | 26 | 27 | 28 | 26 | 28 | 29 | 26 | 28 | 29 | 26 |
Feels °C | 24 | 26 | 26 | 24 | 25 | 26 | 25 | 25 | 25 | 25 | 25 | 26 | 26 | 28 | 28 | 26 | 28 | 29 | 26 |
Swell 1 Height (m) Direction Period (s) | S 16 | E 6 | S 14 | S 13 | S 13 | S 13 | S 12 | SSW 16 | S 12 | SSW 15 | SSW 15 | SSW 14 | ENE 8 | E 8 | S 18 | S 17 | ENE 8 | ENE 8 | S 15 |
| kJ | 582 | 84 | 399 | 225 | 215 | 215 | 138 | 223 | 136 | 199 | 191 | 180 | 191 | 133 | 314 | 459 | 130 | 163 | 275 |
Swell 2 Height (m) Direction Period (s) | N 7 | S 14 | E 15 | E 14 | E 13 | E 13 | SSW 17 | SSW 12 | SSW 16 | S 11 | S 11 | NNE 7 | S 19 | SSW 18 | S 12 | SSW 14 | S 16 | S 16 | SSE 11 |
| kJ | 9 | 329 | 68 | 102 | 89 | 85 | 186 | 46 | 160 | 82 | 85 | 38 | 273 | 329 | 109 | 77 | 422 | 401 | 65 |
Swell 3 Height (m) Direction Period (s) | NW 9 | SSW 11 | SSW 19 | SW 19 | NNE 6 | SSW 17 | ENE 12 | SSE 12 | E 11 | E 11 | SSW 18 | S 10 | S 10 | N 7 | SW 14 | SSE 10 | S 10 | SSE 9 | E 14 |
| kJ | 12 | 40 | 35 | 90 | 12 | 113 | 49 | 48 | 38 | 20 | 31 | 78 | 73 | 36 | 53 | 18 | 51 | 29 | 92 |
Wind waves Height (m) Direction Period (s) | E 7 | E 6 | ENE 6 | ENE 6 | E 6 | E 6 | E 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | E 7 | — | ENE 8 | ENE 8 | ENE 8 | — | — | ENE 8 |
| kJ | 127 | 98 | 94 | 119 | 100 | 151 | 193 | 166 | 232 | 141 | 187 | 171 | — | 211 | 223 | 217 | — | — | 169 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 8 | 0 | 159 | 0 | 7 | 13 | 7 | 0 | 13 | 0 | 7 | 7 | 0 | 0 | 7 | 0 | 0 | 0 | 0 |
Best forecast wave conditions in Oahu | |||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||
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Information about the Nanakuli Blackrocks Surf forecast
The above surf forecast table for Nanakuli Blackrocks provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Nanakuli Blackrocks can be found by selecting the local surf guide option on the grey menu. Our Nanakuli Blackrocks 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 (Nanakuli Blackrocks) 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 Nanakuli Blackrocks 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.
Nanakuli Blackrocks is 6 km (4 miles) from Makakilo City. If you plan a vacation in Oahu, look for hotels and other accommodation in Makakilo City. Makakilo City has rooms for a wide range of budgets as well as car hire and transport links.
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