Number Fours Surf Break

Lat Long: 21.28° N 157.83° W

Number Fours Surf Forecast and Surf Report

Issued: 7 pm 18 Aug 2026 (local time)

Forecast update in  hr  min

Today's Number Fours sea temperature is
26.9° C
0.2° 

Number Fours surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Number Fours surf forecast from 19 Aug 2026:

  • Best quality surf: Thursday 20 Aug, 5AM (local time) - 1.5ft (0.5m), 17s period, SW swell with cross-offshore winds.
  • Most powerful swell: Monday 24 Aug, 8AM (local time) - 7.5ft (2.3m), 7s period, E swell with 585 kJ wave energy.
  • Next surfable swell (1★+): Thursday 20 Aug, 5AM (local time) - 1.5ft (0.5m), 17s 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 5AM. The primary swell is predicted to be 0.5m and 17s 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 2.3m 7s and forecast to arrive on Monday (Aug 24) at 8AM. 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 2AM.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+) 5AM (Thu 20th Aug)1.5ft (0.5m) 17s
Best Surf 5AM (Thu 20th Aug)1.5ft (0.5m) 17s
Most Powerful 8AM (Mon 24th Aug)7.5ft (2.3m) 7s

Table - best surf conditions forecast for Number Fours over the next 16 days.


The Lowdown

Alright folks, Rusty here. Let's have a look at what the next couple of weeks have in store for us at Number Fours. It's a bit of a mixed bag, so let's break it down.

Right off the bat, we've got a couple of small, clean days. Wednesday the 19th has some tiny, weak SW groundswell at 1ft to 2ft with a long 16-second period. The ENE cross-off breeze will keep the surface tidy, but there's just not enough energy in the water to get excited about. The combined energy is weak at 306, so honestly, you might be better off doing something else.

Thursday the 20th is a step up, though still small. The swell pushes to a clean 2ft from the SSW with a longer 18-second period, and that morning the wind drops right out to a light NE breeze. This is clean surf, no doubt, but it's still small. The combined energy is still on the weak side (262). It's a good day for a longboard or a funboard, just to get wet. The tide might be a bit of a factor, so pick your moment.

Friday the 21st stays small at 2ft from the SW, but the wind swings more easterly and becomes a cross-shore, which will put a few ripples on the surface. It's not terrible, but it's not as clean as Thursday. The energy bumps up a little to around 318-347. Still, nothing to write home about.

Now, here's where things go sideways. From Saturday the 22nd, the wind really starts to howl out of the ENE. It's a cross-off breeze, which keeps the surf looking clean, but the wind strength builds through the weekend. By Sunday the 23rd, we've got a strong breeze at 25 mph on top of a junky 6ft to 7ft windswell with a short, crumbly 7-second period. The combined energy is ramping up to 614, but the quality is just poor. This isn't surf for a board; it's a washing machine.

Monday the 24th gets worse. A near gale force ENE wind at 31 mph and a 7ft easterly windswell with a 7-second period. The energy is moderate at 751, but the conditions are poor and there's a risk of thunderstorms. This looks more like a day for the kite surfers than us paddle surfers, to be honest. This messy, windy stretch runs through Tuesday the 25th and Wednesday the 26th. The swell stays in the 6ft to 6ft range with a short period, and the breeze doesn't let up. There are glimmers, like a bump of S swell at 2ft with an 18-second period on Wednesday afternoon, but the wind is still fresh and it's a blip in a pretty poor stretch. The whole run from the 23rd to the 26th is a write-off for decent waves.

Thursday the 27th and Friday the 28th see a drop in size and a shift in direction. The swell swings back around to the south at 3ft, with a period of 14-16 seconds. The wind is still a fresh cross-off from the ENE, but the conditions are clean. It's still small, but there are a few more pulses of energy in the water now. The combined energy is moderate, in the 528-593 range, but it's not quite enough to make it a standout.

Right, so after a week of small, windy slop, things get interesting. As we roll into the first part of September, the models are hinting at something much bigger. On Monday the 1st of September, the swell starts to build from the east, jumping to 7ft in the morning and then up to a solid 8ft in the afternoon. The period stretches out to 11-13 seconds, and the combined energy jumps to 2564 – that's strong energy. The wind is still a fresh cross-off from the ENE, but the wave quality is looking promising. This is for experienced surfers, though, as 8ft is pushing it for beginners.

But the real standout is Tuesday the 2nd of September. We're looking at a solid 10ft of east swell with a long 12-13 second period. The combined energy is a massive 3014. That's very strong, and it's a big call this far out, so don't book the day off work just yet. This is expert territory – 10ft is not for the faint of heart. It's about as promising as it gets in the long-range forecast, but these big swells a week and a half out can change. If it comes together, this is the one.

The window then closes back down on Wednesday the 3rd as the wind picks up to a near gale and the swell drops back to 7ft with a shorter 10-second period, and the energy drops back to 1090. It looks like it might blow out again, so that Tuesday is your ticket.

Overall, the first week is mostly small and windy, with the 20th being your best bet for a clean, small wave. The second week holds a lot more promise, with that big east swell due around the 1st and 2nd of September being the clear highlight. There are a few days of onshore slop in between, so keep your eye on the forecast.

This is Rusty, signing off. Stay stoked.

Short Range Forecast

Mostly dry. Warm (max 27°C on Thu afternoon, min 24°C on Tue night). Wind will be generally light.

Days 5-7 Weather Summary

Light rain (total 5mm), mostly falling on Mon afternoon. Warm (max 27°C on Sat afternoon, min 25°C on Fri night). Winds increasing (light winds from the NE on Fri night, near gales from the ENE by Mon morning).

Wednesday
19
Thursday
20
Friday
21
Saturday
22
Sunday
23
Monday
24
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
1
1
1
1
2
2
2
1
1
1
0
1
0
0
0
0
0
0
1
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
1.2
ENE
8
0.5
SW
16
0.8
E
8
0.5
SW
16
0.6
SSW
18
0.6
SSW
17
0.7
SW
16
0.7
SW
17
0.7
SW
16
0.8
SSW
16
0.7
SW
16
0.7
SW
16
2.1
E
7
1.9
ENE
7
2
ENE
7
2.2
ENE
7
2.1
E
7
2
E
8
2.1
E
8
Wave Graph
Metric surfscale
Energy kJ
159
129
100
129
207
200
274
291
261
322
261
255
457
332
340
448
465
488
573
Wind (km/h)
20
ENE
20
ENE
25
ENE
15
NE
10
NE
10
NNE
5
NE
10
ESE
15
E
15
ENE
35
ENE
35
ENE
35
ENE
40
ENE
40
NE
45
NE
50
ENE
25
E
35
ENE
Wind State
cross-off
cross-off
cross-off
cross-off
cross-off
off
cross-off
cross
cross
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross
cross-off
High Tide
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
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
clear
part cloud
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
part cloud
part cloud
thunderstorm
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:11
6:11
6:11
6:11
6:11
6:11
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:59
6:58
6:57
6:57
6:55
6:54
6:53
 mm
5
12
Temp °C
25
25
26
25
26
27
26
26
27
26
26
27
25
26
26
25
26
26
25
Feels °C
24
25
26
25
28
30
30
29
30
29
26
24
23
23
23
22
22
22
25
  • Map Icons:
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  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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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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