Ammonias Surf Break

Lat Long: 21.95° N 159.35° W

Ammonias Surf Forecast and Surf Report

Issued: 7 pm 31 Aug 2026 (local time)

Forecast update in  hr  min

Today's Ammonias sea temperature is
27.2°C
0.3° 

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


Ammonias surf forecast from 1 Sep 2026:

  • Most powerful swell: Sunday 6 Sep, 5AM (local time) - 7ft (2.2m), 13s period, ENE swell with 1,616 kJ wave energy.

Best Forecast Surf Conditions for Ammonias this week:

The most powerful waves expected at Ammonias in the next 16 days are 2.2m 13s and forecast to arrive on Sunday (Sep 06) at 5AM. Winds are predicted to be cross-shore at the time the swell arrives.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 5AM (Sun 6th Sep)7ft (2.2m) 13s

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


The Lowdown

Alright, Rusty here. Let’s talk about what’s going on at Ammonias.

Right now, we’re looking at a pretty tough stretch. The surf's been mostly marginal or flat, and it’s not going to get good in a hurry. There’s a solid run of onshore and cross-shore winds that will keep things messy. It’s a reef setup, takes swell from the SSE, but we’re mostly seeing ENE windswell – which is all wrong for the place. That means a lot of chop and not much shape.

The water is sitting at 81°, which is basically average for this time of year – nothing unusual there.

Monday afternoon (Aug 31) kicks it off with a 6ft ENE swell, cross wind at 16 mph. It’s just poor. The combined wave energy is weak (778), and the period is short at 8 seconds. Not worth paddling out.

Tuesday morning (Sep 1) is similar: 6ft ENE swell, still cross, still messy. The afternoon is even worse. Same story all the way through Wednesday (Sep 2) – rain showers, cross-onshore wind, chop. No go.

Thursday morning (Sep 3) sees the swell hit 7ft but with fresh cross-shore wind at 19 mph. The combined energy climbs to 1300 (moderate), but the period is still short. The afternoon has a bit of a shift – a 5ft SE swell with a 12 second period. That’s a longer interval, and the energy is 1329. But the wind stays lumpy. It’s still marginal.

Friday (Sep 4) has a 8ft ENE swell in the morning – that’s getting big, going past beginner territory and into intermediate/expert only – but still cross-shore and fresh. The afternoon switches to a 6ft SSE swell with an 11 second period, energy at 1566. Cleaner lines, but the wind is still fresh cross-shore. The stand-out window starts to form here, though it’s still not clean.

Saturday morning (Sep 5) is your first real hope. The swell drops to 5ft from the south, with a nice 12 second period – that’s a proper groundswell. Combined energy is 1448, still moderate, but the wind eases to a moderate cross-shore. The swell direction is getting closer to the optimum SSE. This is the best part of the early run: a bit of juice, a bit of period, and the wind is only cross- not onshore. The afternoon jumps back up to 7ft ENE, but with a good 13 second period and strong energy (2327). Still cross-shore though.

Sunday (Sep 6) brings thunderstorms and the wind goes cross-onshore in the morning – that’s back to poor. The afternoon is marginal again, with a 7ft ENE swell at 13 seconds.

Monday (Sep 7) has the biggest energy of the whole forecast: 2581 in the morning, 8ft ENE with a 12 second period. But it’s cross-shore, and there’s risk of storms. The size is getting into expert-only territory.

Tuesday (Sep 8) sees a shift. Wind swings to light S/SSE, cross-onshore but very gentle. Swell drops to 3ft by the afternoon from the SSW, with a really long 14 second period (energy 629). That’s a clean, long-period groundswell – perfect for a reef like Ammonias, because it won’t close out. The light wind means it could be glassy. The problem is it’s small.

From there, it’s downhill. Wed (Sep 9) back to ENE windswell, 7ft, cross-onshore and choppy. Thu-Sat sees energy drop off hard, swell under 6ft, poor conditions. By Sep 13 onwards: tiny swell under 3ft with long period from the SSW, but no power.

The two standout sessions are Saturday morning Sep 5 and Tuesday afternoon Sep 8.

- Saturday morning (Sep 5): 5ft S swell, 12 second period, moderate cross-shore wind. Not perfect but the best combo of size, direction, and period for the first week. Crowds are likely here often, so it won’t be empty.
- Tuesday afternoon (Sep 8): Only 3ft SSW swell, but with a 14 second period and very light wind – nearly glassy. That’s a pure, clean reef wave if you’ve got a log or a fish.

After Sep 8, don’t expect much. The second week goes flat with small, short-period windswell and poor wind. A long blank run from Sep 11 onward.

So for this stretch, keep an eye on Sep 5 morning and Sep 8 afternoon. Everything else is a scratch.

Rusty.

Short Range Forecast

Moderate rain (total 12mm), heaviest on Mon night. Warm (max 26°C on Tue morning, min 24°C on Mon night). Mainly fresh winds.

Days 5-7 Weather Summary

Light rain (total 8mm), mostly falling on Thu night. Warm (max 26°C on Fri morning, min 24°C on Fri night). Mainly fresh winds.

Tuesday
1
Wednesday
2
Thursday
3
Friday
4
Saturday
5
Sunday
6
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
1
1
0
1
0
1
0
1
1
1
1
1
1
1
2
2
2
2
2
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
1.9
ENE
8
1.8
ENE
8
2.1
ENE
8
2.2
ENE
8
1
S
16
2
ENE
8
2
ENE
8
1.3
SE
12
1.5
SSE
12
2.1
ENE
8
1.5
SSE
11
1.5
S
11
1.6
S
12
1.6
S
12
2.2
ENE
13
2.2
ENE
13
2.1
ENE
13
2.1
ENE
12
Wave Graph
Metric surfscale
Energy kJ
451
421
402
507
568
501
474
450
455
647
532
524
586
678
687
1605
1568
1323
1220
Wind (km/h)
20
NE
25
ENE
25
NE
25
ENE
25
ENE
25
ENE
25
ENE
30
ENE
30
NE
25
ENE
30
ENE
30
NE
25
NE
25
ENE
25
ENE
20
ENE
25
ENE
25
NE
15
NE
Wind State
cross
cross
cross
cross
cross-on
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross
High Tide
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
11:45PM0.03m
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
clear
clear
rain showers
rain showers
rain showers
clear
rain showers
rain showers
rain showers
part cloud
rain showers
part cloud
rain showers
rain showers
rain showers
rain showers
rain showers
part cloud
<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
<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
3
2
2
1
2
1
1
1
1
1
1
2
Temp °C
25
26
26
25
26
26
25
26
26
25
26
26
25
26
26
25
26
26
25
Feels °C
23
25
25
24
26
26
25
25
25
23
24
24
24
25
25
25
26
26
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 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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