Ammonias Surf Break

Lat Long: 21.95° N 159.35° W

Ammonias Surf Forecast and Surf Report

Issued: 1 pm 17 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 18 Aug 2026:

  • Best quality surf: Friday 21 Aug, 2AM (local time) - 2.5ft (0.7m), 16s period, SW swell with cross-offshore winds.
  • Most powerful swell: Monday 24 Aug, 8PM (local time) - 7ft (2.1m), 7s period, ENE swell with 431 kJ wave energy.
  • Next surfable swell (1★+): Friday 21 Aug, 2AM (local time) - 2.5ft (0.7m), 16s period with SW 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 Friday (Aug 21) at 2AM. The primary swell is predicted to be 0.7m and 16s period with a secondary swell of 1.0m and 7s. 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 2.1m 7s and forecast to arrive on Monday (Aug 24) at 8PM. Winds are predicted to be cross-shore 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 5PM.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+) 2AM (Fri 21st Aug)2.5ft (0.7m) 16s
Best Surf 2AM (Fri 21st Aug)2.5ft (0.7m) 16s
Most Powerful 8PM (Mon 24th Aug)7ft (2.1m) 7s

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


The Lowdown

Alright, Rusty here. I’m looking at the forecast for Ammonias, and it’s pretty grim over the next 16 days.

We’re staring down a long stretch of poor conditions. The wind is mostly cross-on or cross-shore from the east and northeast, blowing 12 to 15 mph, and it’s just messing up the water. The water temperature is about 80°F, which is normal for this time of year, so at least the water’s not cold.

The first tiny ray of hope is around Thursday, August 20th. The swell drops to about 2 feet from the SSW with a period of 18 seconds, that’s a long-period groundswell, but there’s hardly any energy in it (268). The wind will be light, maybe a little cross, so it might be clean, but it’s barely a wave. It’s described as "marginal."

We get a bump in size on Sunday, August 23rd, with swell from the ENE pushing 6 feet, but the period is a short 7 seconds, just windswell. The wind is still 15 mph and cross-shore, so it’s going to be a choppy, lumpy mess. The same story repeats for days – a bit of size, but bad wind and short period.

The closest we get to something half decent is around Wednesday, August 26th, and the following weekend. The swell builds from 7 to 8 feet, but it’s all short-period ENE windswell (6-8 seconds), and the wind is still 12-15 mph. The energy gets strong (up to 1357), but with those conditions, it’s just a big, sectiony, blown-out mess. For a reef break, that’s not good. It’s too big for beginners (over 5 feet) and close to expert-only (over 8 feet), but with this wind, it’s not even good for experts. The setup here is a reef, and with that short-period, onshore-driven swell, it’s going to be a washing machine. It might look more interesting for kite surfing than paddle surfing.

Heading into September, the swell fades back to under 3 feet, and the wind stays strong from the east. The best we can hope for is a tiny, clean day around the 20th of August, but it’s a long shot. This is a real blank run for Ammonias.

Rusty.

Short Range Forecast

Light rain (total 3mm), mostly falling on Mon afternoon. Warm (max 26°C on Mon afternoon, min 24°C on Mon night). Wind will be generally light.

Days 5-7 Weather Summary

Light rain (total 2mm), mostly falling on Sat night. Warm (max 27°C on Fri afternoon, min 24°C on Thu night). Wind will be generally light.

Mon
17
Tuesday
18
Wednesday
19
Thursday
20
Friday
21
Saturday
22
Sunday
23
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
1
0
0
0
0
0
0
1
1
2
1
1
1
0
0
0
1
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)
1.8
ENE
7
0.8
S
14
1.4
ENE
7
0.7
S
13
0.6
S
13
0.5
SW
16
1.1
ENE
6
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
1.7
ENE
7
1.6
ENE
7
1.6
ENE
7
Wave Graph
Metric surfscale
Energy kJ
349
233
165
165
112
129
103
130
207
195
278
255
258
322
261
220
218
255
230
223
Wind (km/h)
20
E
20
ENE
20
ENE
20
ENE
20
ENE
15
ENE
15
ENE
15
NE
15
ENE
10
ENE
10
NE
10
ESE
10
ESE
10
ENE
20
ENE
20
ENE
20
ENE
25
ENE
25
NE
25
NE
Wind State
cross-on
cross
cross-on
cross
cross-on
cross-on
cross
cross
cross
cross
cross-off
cross-on
on
cross
cross-on
cross
cross
cross
cross
cross
High Tide
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
1:46PM0.62m
1:16AM0.25m
Low Tide
00:55AM0.06m
3:13PM0.30m
1:28AM0.08m
2:14AM0.09m
3:21AM0.10m
9:24PM0.19m
9:13PM0.18m
5:45AM0.08m
9:16PM0.18m
thunderstorm
part cloud
part cloud
clear
part cloud
part cloud
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
thunderstorm
clear
part cloud
part cloud
<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
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
7:06
7:06
7:05
7:04
7:02
7:01
7:01
 mm
3
2
Temp °C
26
25
26
26
25
25
26
24
26
26
25
26
27
26
26
27
25
26
26
25
Feels °C
27
26
26
26
26
25
26
25
27
28
27
29
30
29
27
28
26
26
26
24
  • 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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