Ammonias Surf Break

Lat Long: 21.95° N 159.35° W

Ammonias Surf Forecast and Surf Report

Issued: 1 am 31 Aug 2026 (local time)

Forecast update in  hr  min

Today's Ammonias sea temperature is
27.3°C
0.4° 

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


Ammonias surf forecast from 31 Aug 2026:

  • Most powerful swell: Sunday 6 Sep, 8AM (local time) - 8ft (2.5m), 13s period, ENE swell with 2,091 kJ wave energy.

Best Forecast Surf Conditions for Ammonias this week:

The most powerful waves expected at Ammonias in the next 16 days are 2.5m 13s and forecast to arrive on Sunday (Sep 06) at 8AM. Winds are predicted to be cross-onshore at the time the swell arrives.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 8AM (Sun 6th Sep)8ft (2.5m) 13s

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


The Lowdown

Alright folks, Rusty here with a look at what’s on the cards for Ammonias over the next couple of weeks. Gotta be straight with you – it’s a bit of a slow burn for most of it, but there’s a potential gem tucked away in the second week if you’ve got the patience.

We’ve got swell at Ammonias for the whole run, but the wind and overall quality are a real battle for the first week and a half. Expect a pretty average run from now through to the end of the first week of September. The water temp is sitting at about 81°, which is pretty normal for this time of year – no surprises there.

Monday 31st August kicks off with a solid 7 ft of short-period (8 seconds) ENE swell, pushing through about 736 (moderate wave energy). Sounds okay, but it’s hammered by a moderate cross-breeze at 16 mph, leaving a proper cross-chop on the surface. The surf is pretty poor – not worth getting wet for. That pattern sticks around. Tuesday 1st September is similar, 6 ft ENE swell (895 energy) but again, that darn cross-wind makes a mess of it. Wednesday 2nd September sees a brief spike in the afternoon with a 3 ft S swell showing a long period of 16 seconds (867 energy), which carries some nice shape, but it’s still battling a moderate cross-breeze.

Through Thursday 3rd to Saturday 5th September, the swell picks up to 7 ft – 8 ft (energy climbing from 1018 to 1658 – solid moderate to strong energy), but the wind stays stuck in a fresh cross or cross-onshore pattern. The onshore wind on the 3rd and 5th makes for lumpy, choppy conditions. It’s a write-off for a clean paddle.

Sunday 6th and Monday 7th September bring a shift. The swell hangs around 8 ft to 8 ft, but the period jumps to 12-13 seconds (energy hitting 2442 and 2780 – strong). That’s proper groundswell energy there, which usually means better shaped waves and longer lulls. The problem? We’re still looking at moderate cross-breezes and some chop. It’s *closer* to something workable, but the wind just won’t let it be clean. Tides might be a factor too.

Now, Tuesday 8th September is the real standout. Mark this one in your diary if you’re an expert surfer. The morning session looks absolutely pumping. We get a 18 ft E swell (7611 – very strong wave energy) with a solid 11-second period. And the magic ingredient? A light offshore cross-off breeze from the west at just 6 mph. That’s clean surf, folks. This is exceptional, but there’s a heavy caveat: 18 ft is serious, expert-only territory. It’s a big, powerful groundswell at a reef break, demanding respect. The afternoon drops to 15 ft (4195 energy) but gets hit by a moderate cross-swell from the SW, so morning is the window.

After that, it settles down. Wednesday 9th September sees the swell drop back to 7 ft (1330 energy) with a cross-onshore wind ruining the clean-up. Thursday 10th to Saturday 12th September is back to average 6 ft to 7 ft ENE windswell (medium energy around 500-800) with a persistent moderate cross-breeze. Nothing to write home about.

Then the tail end of the window looks sweet. Sunday 13th to Monday 14th September is a great little run. The swell holds steady at 6 ft to 7 ft from the ENE (8 seconds), but the wind drops right out. We’re talking glassy conditions from Sunday afternoon right through Monday – 0 mph winds. Expect very good surf conditions. That’s a clean, fun-sized swell, perfect for a relaxed session. Crowds are often here, so you’ll have some company, but with conditions that good, it’s worth it. Tuesday 15th September drops to 5 ft with a light cross breeze – back to average, but okay for a paddle.

So, the true standout is Tuesday 8th September for the expert crew – that 18 ft morning session is as good as it gets if you’ve got the bottle. For most of us, keep an eye on Sunday 13th and Monday 14th September for some clean, glassy fun.

Rusty.

Short Range Forecast

Moderate rain (total 12mm), heaviest on Mon morning. Warm (max 27°C on Wed afternoon, min 24°C on Mon night). Wind will be generally light.

Days 4-6 Weather Summary

Moderate rain (total 14mm), heaviest on Thu afternoon. Warm (max 27°C on Sat afternoon, min 25°C on Thu morning). Mainly fresh 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
Rating
(10 max)
0
0
1
1
0
0
1
1
1
0
1
1
1
1
1
0
1
0
0
2
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
2
ENE
8
1.8
ENE
8
2
ENE
8
1.9
ENE
8
1.7
ENE
8
1.8
ENE
8
1.9
ENE
8
0.9
S
16
0.9
S
15
2.2
E
8
2.1
ENE
8
2.4
ENE
8
2.4
ENE
8
2.3
ENE
8
2.2
ENE
8
2.4
ENE
8
2.2
ENE
8
2.5
ENE
8
2.4
ENE
13
2.3
ENE
13
2.3
ENE
13
Wave Graph
Metric surfscale
Energy kJ
428
392
451
421
383
403
443
406
390
566
507
672
707
669
570
689
585
765
1901
1661
1645
Wind (km/h)
25
ENE
25
ENE
20
ENE
25
ENE
25
NE
25
ENE
20
ENE
20
NE
25
ENE
30
ENE
30
NE
30
NE
30
ENE
30
NE
25
ENE
25
ENE
25
ENE
25
ENE
25
E
25
ENE
20
ENE
Wind State
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross-on
cross
cross
cross
cross
cross
cross-on
cross
cross-on
cross-on
cross
cross-on
High Tide
5:08PM0.42m
6:57AM0.52m
5:24PM0.35m
8:09AM0.55m
5:17PM0.30m
9:35AM0.57m
10:57AM0.61m
12:04PM0.65m
11:37PM0.20m
12:57PM0.68m
00:45AM0.25m
Low Tide
11:48AM0.20m
11:45PM0.03m
1:02PM0.26m
00:18AM0.03m
3:05PM0.29m
1:01AM0.04m
2:01AM0.05m
3:24AM0.06m
8:23PM0.17m
8:30PM0.15m
rain showers
rain showers
rain showers
rain showers
clear
rain showers
rain showers
clear
rain showers
rain showers
rain showers
cloud
rain showers
cloud
rain showers
rain showers
thunderstorm
rain showers
thunderstorm
thunderstorm
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:20
6:20
6:20
6:20
6:20
6:20
6:20
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:54
6:53
6:52
6:52
6:51
6:50
6:49
 mm
2
1
1
1
3
2
2
2
2
1
1
2
2
4
3
3
3
Temp °C
26
26
25
26
26
25
26
27
26
26
26
25
26
26
25
26
27
26
27
27
26
Feels °C
25
25
24
25
25
25
26
27
26
25
25
23
23
24
23
26
27
26
27
27
26
  • Map Icons:
  • Break
  • 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 Ammonias Surf forecast

The above surf forecast table for Ammonias provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Ammonias can be found by selecting the local surf guide option on the grey menu. Our Ammonias 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 (Ammonias) 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 Ammonias 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.

Are you planning a vacation in Kaua'i? If you are looking for accommodation near Ammonias, camping, hotels and condos and appartments in Kaua'i, consider staying in Nawiliwili which is 2 km (1 miles) away. Alternatively, find information about places to stay and car hire in Lihue - Kauai which is 3 km (2 miles) away

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