Ammonias Surf Break

Lat Long: 21.95° N 159.35° W

Ammonias Surf Forecast and Surf Report

Issued: 7 pm 09 Aug 2026 (local time)

Forecast update in  hr  min

Today's Ammonias sea temperature is
26.6° C
0.1° 

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


Ammonias surf forecast from 10 Aug 2026:

  • Best quality surf: Monday 17 Aug, 2AM (local time) - 13ft (4.0m), 12s period, ENE swell with cross-offshore winds.
  • Most powerful swell: Monday 17 Aug, 2AM (local time) - 13ft (4.0m), 12s period, ENE swell with 4,863 kJ wave energy.
  • Next surfable swell (1★+): Sunday 16 Aug, 8PM (local time) - 11ft (3.5m), 12s period with ENE 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 Sunday (Aug 16) at 8PM. The primary swell is predicted to be 3.5m and 12s period with a secondary swell of 0.7m and 13s. Another secondary swell of 0.6m and 16s is also forecast. The wind is predicted to be offshore as the swell arrives.

The most powerful waves expected at Ammonias in the next 16 days are 4.0m 12s and forecast to arrive on Monday (Aug 17) at 2AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 12s period and expected on Thursday (Aug 13) at 11AM.

Wave TypeTime (HST) & Date Wave Height & Period
Next good surf (1 star+) 8PM (Sun 16th Aug)11ft (3.5m) 12s
Best Surf 2AM (Mon 17th Aug)13ft (4.0m) 12s
Most Powerful 2AM (Mon 17th Aug)13ft (4.0m) 12s

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


The Lowdown

Alright folks, Rusty here. Let's have a look at what's on the cards for Ammonias over the next couple of weeks. It’s a mixed bag, so bear with me.

Right off the bat, the first few days are a bit of a struggle. We’ve got some small swell rolling in on Monday the 10th, 2ft to 3ft from the SSW, but the wind is a cross-shore from the ENE at 12 mph, making for a messy, cross-chop surface. The combined swell energy is moderate at best (606-557). It’s surfable if you’re desperate, but it’s not going to be pretty. Tuesday the 11th is much the same story, with a bit more wind making it even choppier in the morning. Wednesday the 12th sees a pulse of new longer-period S swell (18 seconds) pushing the height up to 3ft – 4ft, but that cross-onshore wind keeps the surface lumpy. The energy ticks up to moderate (1119-1193), but the quality is just not there.

Thursday the 13th and Friday the 14th stay in that 4ft to 5ft range from the S, but that fresh NE breeze on Friday (18 mph) is going to wreck the surface completely. You’ll be fighting a lumpy cross-chop.

Now, here’s the first standout. Keep an eye on Saturday the 15th and Sunday the 16th. We get a shift in the swell direction to the ENE. Saturday morning sees about 7ft from the ENE with a short period (8 seconds), but by the afternoon the wind goes cross-offshore from the NNE at 15 mph. That’s clean! Sunday the 16th is similar, with the swell building to a solid 10ft from the ENE, period stretching to 13 seconds, and more of that sweet cross-offshore breeze (NNE 18 mph in the morning, NNW 15 mph in the afternoon). The combined swell energy jumps to very strong (2811-3223). However, that 10ft is getting big for the average punter – this is expert territory. And with that long period (12-13 seconds), it'll be lining up nicely, but at a beach break like this, it might be a bit straight and dumpy. Still, if you’ve got the skills, Sunday afternoon is your window.

Then things go a bit mad. Monday the 17th throws a massive 20ft ENE swell at us with a combined energy reading of 9177 – we’re talking very strong, serious power. But it comes with a cross-shore wind and a risk of thunderstorms. That’s big, dangerous, and messy. The afternoon drops to 18ft from the E, but the cross-onshore wind from the S makes it a washing machine. This setup looks way more interesting for kite surfing than paddle surfing.

After that chaos, the second week settles right down. Tuesday the 18th sees the swell drop back to 5ft – 6ft from the ENE, with periods under 10 seconds. The winds are onshore or cross-onshore, so the quality is poor. Wednesday the 19th is much the same with weak, short-period wind swell.

Things get quiet toward the end of the week. Thursday the 20th and Friday the 21st see the swell shrink to 2ft – 2ft, but the direction swings back to the SSW with very long periods (18-19 seconds). The energy is weak though, and the cross-wind keeps it choppy. Saturday the 22nd is the flattest day of the run, with only 2ft – 2ft of weak, short-period junk.

Into the final week of the forecast, we get another promising pulse. Sunday the 23rd and Monday the 24th see the SSW swell build back up, with periods jumping to a very long 18-22 seconds. By Monday morning we’re looking at 6ft from the SSW with a period of 18 seconds and combined energy hitting 2456 (strong). The wind stays cross-shore from the ENE, so it won't be glassy, but for a point or reef setup, that long-period groundswell would be a dream. At Ammonias, a reef break, this is the kind of window that gets the blood pumping. That 6ft with a long period will have some real grunt and shape. Tuesday the 25th holds at 5ft from the SSW with 16-second periods, still solid but easing.

So, the two honest standouts here are Sunday the 16th for the big, clean, expert-only ENE swell, and then Monday the 24th for the long-period SSW groundswell that should deliver the best combination of size, power, and shape for the more experienced crew at the reef.

Rusty

Short Range Forecast

Light rain (total 2mm), mostly falling on Mon morning. Warm (max 27°C on Tue morning, min 24°C on Tue night). Wind will be generally light.

Days 5-7 Weather Summary

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

Monday
10
Tuesday
11
Wednesday
12
Thursday
13
Friday
14
Saturday
15
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
1
1
2
0
1
0
0
2
2
2
1
2
0
0
1
1
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)
0.7
SSW
16
0.7
SSW
16
0.8
SSW
15
0.8
SSW
15
0.7
SSW
15
0.8
SSW
14
0.7
S
20
1
S
18
1.1
S
18
1.5
S
16
1.4
S
16
1.4
S
15
1.3
S
15
1.2
S
14
1.1
S
14
2.1
ENE
7
2.2
ENE
8
2.3
ENE
9
2.5
ENE
8
Wave Graph
Metric surfscale
Energy kJ
263
259
300
296
222
269
373
635
741
1178
1004
906
743
598
496
482
646
791
1000
Wind (km/h)
20
ENE
20
ENE
20
ENE
15
NE
15
ENE
15
ENE
20
ENE
20
ENE
20
NE
20
ENE
20
NE
25
NE
25
NE
30
NE
25
NE
25
NE
25
NE
25
NNE
25
NNE
Wind State
cross-on
cross
cross
cross
cross-on
cross
cross-on
cross-on
cross
cross
cross
cross
cross
cross
cross
cross
cross
cross-off
cross-off
High Tide
1:24AM0.22m
2:47PM0.75m
2:17AM0.26m
3:26PM0.74m
3:06AM0.30m
4:02PM0.71m
3:54AM0.34m
4:34PM0.66m
4:44AM0.37m
5:03PM0.59m
5:36AM0.41m
5:29PM0.52m
Low Tide
9:35PM0.15m
7:01AM-0.05m
9:56PM0.13m
7:54AM-0.06m
10:20PM0.12m
8:43AM-0.04m
10:44PM0.10m
9:30AM-0.00m
11:09PM0.08m
10:17AM0.05m
11:35PM0.07m
11:06AM0.12m
00:00AM0.06m
clear
rain showers
part cloud
part cloud
clear
clear
clear
clear
clear
clear
part cloud
part cloud
part cloud
part cloud
clear
part cloud
part cloud
part cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:13
6:13
6:13
6:13
6:13
6:15
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
7:12
7:10
7:10
7:09
7:08
7:08
7:07
 mm
2
Temp °C
25
26
26
25
27
27
25
26
26
25
27
27
25
26
27
26
26
26
25
Feels °C
25
27
26
26
28
27
26
26
26
25
26
26
24
25
25
25
24
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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