Ammonias Surf Break

Lat Long: 21.95° N 159.35° W

Ammonias Surf Forecast and Surf Report

Issued: 1 am 18 Aug 2026 (local time)

Forecast update in  hr  min

Today's Ammonias sea temperature is
26.5° 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 18 Aug 2026:

  • Best quality surf: Saturday 22 Aug, 2AM (local time) - 2.5ft (0.8m), 16s period, SSW swell with cross-offshore winds.
  • Most powerful swell: Tuesday 25 Aug, 5AM (local time) - 8ft (2.5m), 8s period, ENE swell with 867 kJ wave energy.
  • Next surfable swell (1★+): Thursday 20 Aug, 8PM (local time) - 2ft (0.6m), 16s period with SSW swell.

Best Forecast Surf Conditions for Ammonias this week:

The surf forecast for Ammonias over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Aug 20) at 8PM. The primary swell is predicted to be 0.6m and 16s period. The wind is predicted to be cross-offshore as the swell arrives.

The most powerful waves expected at Ammonias in the next 16 days are 2.5m 8s and forecast to arrive on Tuesday (Aug 25) at 5AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 7s period and expected on Friday (Aug 21) at 5AM.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+) 8PM (Thu 20th Aug)2ft (0.6m) 16s
Best Surf 2AM (Sat 22nd Aug)2.5ft (0.8m) 16s
Most Powerful 5AM (Tue 25th Aug)8ft (2.5m) 8s

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


The Lowdown

Alright folks, Rusty here. Let’s break it down.

The outlook for Ammonias is a bit of a slog for the first week. The swell is small and the wind is mostly cross or cross-on, keeping things messy. The water temp is 80°, which is right around normal for this time of year, nothing unusual.

We start off with a few days of tiny surf. Tuesday the 18th and Wednesday the 19th have waves around 1ft to 2ft, but the wind is cross and the conditions are poor. Not worth paddling out. Thursday the 20th and Friday the 21st stay small, with a slight improvement on Friday morning when the wind goes offshore from the SE, light breeze at 6 mph. The swell is still only 2ft from the SSW with a long 17-second period, but that offshore wind makes it look clean. It’s marginal, but if you’re keen, Friday morning is the only real window in the first week. The combined energy is moderate (343).

Saturday the 22nd and Sunday the 23rd see a jump in size, but the quality is gone. On Sunday morning, swell hits 7ft from the ENE, but it’s short period at 7 seconds and cross-shore wind at 16 mph. It’s messy. The energy is moderate (761), but the setup is more interesting for kite surfing than paddle surfing.

From Monday the 24th through to Wednesday the 27th, we see a run of bigger swell, 8ft to 8ft, but the wind is cross or cross-on, and the period is short (7-8 seconds). This is lumpy and bumpy, not fun. The energy gets strong, hitting 1053 on Monday afternoon, but the conditions don’t match. For experts only, and even then, it’s a tough paddle.

There’s a bit of a gap with no real recommendations until the very end of the period. The standout in the whole 16-day window looks like the morning of Tuesday the 2nd of September. We’ve got a solid 7ft swell from the south, period at 11 seconds, and light offshore wind from the SSE at 6 mph. The combined energy is very strong at 2014. This is the one to mark on the calendar. It’s a long way out, so treat it as promising but not guaranteed. For a reef break like Ammonias, that longer period groundswell should set up nicely. Expect some good, clean waves, but with crowds likely at this spot, get there early.

Overall, don’t get your hopes up for the first week. The second week shows more life, especially that Tuesday the 2nd. Keep an eye on it.

Rusty.

Short Range Forecast

Mostly dry. Warm (max 26°C on Tue afternoon, min 24°C on Tue night). Wind will be generally light.

Days 4-6 Weather Summary

Light rain (total 3mm), mostly falling on Sat night. Warm (max 27°C on Fri afternoon, min 24°C on Sun night). Wind will be generally light.

Tuesday
18
Wednesday
19
Thursday
20
Friday
21
Saturday
22
Sunday
23
Monday
24
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
0
0
0
0
0
1
2
1
1
3
0
0
1
0
0
1
1
1
1
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
1.4
ENE
7
1.3
ENE
7
1.3
ENE
6
0.5
SW
16
0.4
SSW
16
1.2
ENE
8
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
2
ENE
7
1.9
ENE
7
2
ENE
7
2.3
ENE
7
2.3
ENE
7
2.5
ENE
8
Wave Graph
Metric surfscale
Energy kJ
165
165
112
129
103
172
207
195
278
255
258
322
261
217
220
382
366
394
545
588
829
Wind (km/h)
20
ENE
20
ENE
20
ENE
15
ENE
15
ENE
15
ENE
15
NE
15
NE
10
NNE
10
SE
10
SE
5
NNE
20
ENE
20
ENE
20
ENE
25
NE
30
NE
25
NE
25
ENE
30
ENE
30
ENE
Wind State
cross-on
cross
cross-on
cross
cross
cross
cross
cross
cross-off
on
on
cross-off
cross-on
cross
cross
cross
cross
cross
cross
cross
cross
High Tide
8:46AM0.48m
5:31PM0.30m
10:06AM0.50m
11:20AM0.53m
12:20PM0.56m
11:30PM0.20m
1:07PM0.59m
00:35AM0.22m
1:46PM0.62m
1:16AM0.25m
2:19PM0.63m
1:51AM0.28m
Low Tide
3:13PM0.30m
1:28AM0.08m
2:14AM0.09m
3:21AM0.10m
9:24PM0.19m
9:13PM0.18m
5:45AM0.08m
9:16PM0.18m
6:37AM0.05m
9:23PM0.17m
part cloud
part cloud
part cloud
part cloud
part cloud
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
thunderstorm
clear
clear
part cloud
clear
rain showers
rain showers
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:16
6:16
6:16
6:16
6:16
6:16
6:16
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
7:06
7:05
7:04
7:02
7:01
7:01
7:00
 mm
3
1
4
Temp °C
25
26
24
25
26
25
26
26
25
26
27
26
26
27
25
26
26
25
26
26
25
Feels °C
25
26
25
25
26
26
27
27
28
29
30
30
27
28
26
26
25
24
26
25
24
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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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