Ammonias Surf Break

Lat Long: 21.95° N 159.35° W

Ammonias Surf Forecast and Surf Report

Issued: 7 pm 16 Aug 2026 (local time)

Forecast update in  hr  min

Today's Ammonias sea temperature is
26.6° C
0.2° 

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


Ammonias surf forecast from 17 Aug 2026:

  • Most powerful swell: Monday 17 Aug, 2AM (local time) - 6.5ft (2.0m), 8s period, ENE swell with 554 kJ wave energy.

Best Forecast Surf Conditions for Ammonias this week:

The most powerful waves expected at Ammonias in the next 16 days are 2.0m 8s and forecast to arrive on Monday (Aug 17) at 2AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 6s period and expected on Thursday (Aug 20) at 8AM.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 2AM (Mon 17th Aug)6.5ft (2.0m) 8s

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


The Lowdown

Alright, Rusty here. Let’s get into it for Ammonias.

Honestly, looking at the next couple of weeks, we’ve got a long, frustrating wait ahead. The first real surf worth paddling out for doesn’t show up until the 28th of August, so from now until then, it’s mostly just chopped-up leftovers, onshore junk, and tiny swell. It’s gonna be a grind, with nearly two weeks of poor conditions making it tough to find anything clean.

Starting this Sunday afternoon, the 16th, the swell is a solid 10ft from the ENE, but the wind is cross-on at 16 mph, so it’s a mess – choppy with thunderstorm risk. The water temp is about average for the time of year at 80°. Not worth it.

Through Monday the 17th into the 18th, the swell drops to under 3ft with long-period S and SW swells, but again, that cross-on wind keeps things ugly. Tuesday the 19th sees the swell bottom out. We get a few days of marginal conditions from the 20th to the 22nd, with tiny 2ft SSW swell and light cross-shore or onshore winds, but nothing you’d write home about.

From the 23rd to the 27th, we get pulses of short-period ENE swell around 5-6ft, but the wind never really cleans up – mostly cross or cross-on with a chop. The combined energy is moderate (around 409-782) but the quality is poor.

Now, the standout window arrives late August. The first real chance is Friday the 28th of August, when an 8ft ENE swell rolls in with an 11-second period. Combined energy jumps to a strong 1601. The wind is still cross-on in the morning, making it choppy and 8ft is getting into expert-only territory for this reef. But the afternoon looks better, with cross-shore wind and the same size, earning a marginal nod. This could be one for the experienced crew who don’t mind a bit of chop.

The highlight of the entire run is Saturday the 29th of August. That 8ft ENE swell hangs around, and the period stretches to a very long 12 seconds – this is groundswell energy, making for better-shaped waves. The combined energy is very strong (over 2949). The wind stays cross-shore at 13-16 mph. For a reef setup, that long period can mean nice lines, but it’s still a big swell. The afternoon on the 29th is the best on offer with a score of 3/10 and cross-shore wind. Still, it’s big and powerful, so experts only.

Sunday the 30th drops to 6ft with a 10-second period, and then we fade back into small SSW swell by Monday the 31st. Nothing else stands out.

At Ammonias, this reef break needs an offshore wind from the NW to really shine, and we don't get that at all, so we are working with a cross-shore angle. Crowds are often a factor here when it’s good, which could happen on the 29th. This is a reef break, so that long-period groundswell will really wrap in and offer better shape but can get a bit straight at times. For the bulk of the next two weeks, this setup with onshore wind and moderate to strong swell just looks more interesting for kite surfing than paddle surfing, honestly.

Rusty.

Short Range Forecast

Moderate rain (total 13mm), heaviest on Sun night. Warm (max 26°C on Sun night, min 24°C on Mon night). Wind will be generally light.

Days 5-7 Weather Summary

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

Monday
17
Tuesday
18
Wednesday
19
Thursday
20
Friday
21
Saturday
22
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
1
0
0
1
0
0
0
0
0
0
0
1
1
0
0
2
0
0
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
1.7
ENE
8
1.7
ENE
7
1.7
ENE
7
0.7
S
13
0.7
S
13
0.6
S
13
0.5
SW
16
1.1
ENE
7
0.5
SW
16
0.6
SSW
18
0.6
SSW
17
0.7
SW
16
0.7
SSW
17
0.7
SW
16
0.8
SSW
16
0.7
SW
16
0.7
SSW
16
0.7
SSW
16
Wave Graph
Metric surfscale
Energy kJ
554
335
314
247
170
165
115
129
99
130
207
195
278
255
258
322
261
217
212
Wind (km/h)
20
ESE
25
E
25
ENE
20
ENE
20
ENE
20
ENE
20
ENE
20
ENE
15
ENE
20
ENE
15
ENE
15
NE
15
ENE
15
E
10
E
5
NE
15
ENE
15
ENE
15
ENE
Wind State
cross-on
cross-on
cross-on
cross
cross-on
cross
cross
cross-on
cross
cross
cross
cross
cross
cross-on
cross-on
cross
cross-on
cross-on
cross-on
High Tide
7:34AM0.46m
6:01PM0.36m
8:46AM0.48m
5:31PM0.30m
10:06AM0.50m
11:20AM0.53m
12:20PM0.56m
11:30PM0.20m
1:07PM0.59m
00:35AM0.22m
Low Tide
00:26AM0.06m
1:11PM0.26m
00:55AM0.06m
3:13PM0.30m
1:28AM0.08m
2:14AM0.09m
3:21AM0.10m
9:24PM0.19m
9:13PM0.18m
thunderstorm
thunderstorm
thunderstorm
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:15
6:16
6:16
6:16
6:16
6:16
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
7:07
7:06
7:06
7:05
7:04
7:02
7:01
 mm
9
3
1
Temp °C
26
26
26
25
26
26
25
26
26
25
26
26
25
26
27
25
27
27
26
Feels °C
27
28
27
26
27
26
26
27
26
26
27
27
27
28
29
28
28
28
27
  • 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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