
Surf Forecasts:
Ammonias surf forecast from 11 Aug 2026:
- Most powerful swell: Tuesday 18 Aug, 5AM (local time) - 13ft (4.0m), 12s period, ENE swell with 4,862 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 4.0m 12s and forecast to arrive on Tuesday (Aug 18) at 5AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 4.0m 11s period and expected on Tuesday (Aug 18) at 8AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 5AM (Tue 18th Aug) | 13ft (4.0m) 12s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Right, folks, Rusty here. Let’s have a look at what’s on offer for Ammonias over the next couple of weeks. Straight up, I gotta be honest with you – it’s a pretty bleak picture. The whole 16-day window is looking mostly flat or messy, with only a few flickers of hope that are more about the idea of a wave than a real session.
The pattern is dominated by onshore and cross-shore winds, choppy conditions, and a lot of small, weak swell. The water’s sitting at 80°, which is pretty much bang on average for this time of year – nothing weird there.
The first real chance to even think about paddling out comes on Wednesday, August 12. We’ve got a bit of a pulse from the south, with a long period of 18 seconds, pushing the swell up to 4 ft. The combined energy is moderate (1210), but the wind is a moderate cross-shore, creating a cross-chop. It’s a marginal call, but if you’re desperate, the morning of the 12th is the cleanest it gets, with a light cross-onshore. Still, it’s not great.
The same goes for Thursday, August 13. The morning offers 5 ft of S swell at 16 seconds, with moderate energy (1193), but again that cross-shore wind ruins the party. Afternoon gets worse. Friday and Saturday are a write-off with fresh cross-shore winds and lumpy, choppy conditions.
Now, Sunday, August 16, is the only proper standout in the whole window. The afternoon sees a clean, cross-offshore breeze from the NNE at 35 km/h. The swell is 8 ft from the ENE, with a period of 11 seconds, and the energy is strong (1534). This is a solid, legitimate swell size, but at 8 ft, it’s getting into the “experts only” territory. It’s a reef break that needs the right direction, and the optimum swell here is from the SSE, so this ENE swell is a bit off-angle. Still, the clean conditions are a major positive. It’s the best on offer, but it’s a long way out, so keep an eye on it. Crowds are likely at this spot.
After that, it’s back to the doldrums. Monday, August 17, sees a much bigger 10 ft swell from the ENE, but with strong onshore winds and a storm risk, it’s a total mess. Then the rest of the second week is a long, flat gap of tiny, weak SSW swell and onshore wind. There’s a bit of a bump on the 25th and 26th of August, with moderate energy and a chance of a marginal wave, but the wind is still cross-onshore and choppy. It’s a long, quiet run.
So, here’s the bottom line: if you’re desperate for a wave, the morning of Wednesday, August 12, is the pick of the first week, but it’s marginal. The only real standout is Sunday, August 16, in the afternoon, with clean conditions and a solid 8 ft swell – but it’s for experts, and it’s a long way off. For the rest of the time, it’s a long blank run. The forecast can change, but right now, it’s a tough one.
Rusty.
Short Range ForecastMostly dry. Warm (max 27°C on Tue morning, min 24°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 11mm), heaviest on Sun night. Warm (max 27°C on Fri afternoon, min 25°C on Fri night). Mainly fresh winds. | ||||||||||||||||||||
Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | |||||||||||||||
AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map | |||||||||||||||||||||
Wave Height (m) Direction Period (s) | SSW 15 | SSW 14 | S 20 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 | S 14 | S 14 | S 14 | ENE 8 | ENE 9 | ENE 10 | ENE 11 | ENE 11 | ENE 11 | ENE 11 | ENE 12 | ENE 12 |
Wave Graph | |||||||||||||||||||||
222 | 269 | 373 | 515 | 741 | 1178 | 1004 | 784 | 743 | 598 | 496 | 394 | 428 | 482 | 942 | 1249 | 1194 | 1230 | 1447 | 2164 | 3156 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross | cross-on | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross-off | cross | cross | cross-on | cross-on |
High Tide | 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 | 6:32AM0.43m | 5:50PM0.44m | 7:34AM0.46m | 6:01PM0.36m | ||||||||
Low Tide | 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 | 12:01PM0.20m | 00:26AM0.06m | 1:11PM0.26m | 00:55AM0.06m | ||||||||
6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:15 | — | — | 6:15 | — | — | 6:15 | — | — | |
— | 7:10 | — | — | 7:09 | — | — | 7:08 | — | — | 7:08 | — | — | 7:07 | — | — | 7:07 | — | — | 7:06 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 4 | 1 | — | 5 | 4 | 4 | 9 |
Temp °C | 27 | 27 | 25 | 26 | 26 | 25 | 27 | 27 | 25 | 26 | 27 | 26 | 27 | 27 | 25 | 27 | 27 | 25 | 25 | 26 | 25 |
Feels °C | 28 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 25 | 25 | 25 | 26 | 27 | 24 | 26 | 26 | 23 | 23 | 26 | 25 |
Swell 1 Height (m) Direction Period (s) | SSW 15 | SSW 14 | SSW 13 | SSW 13 | S 18 | S 16 | S 16 | S 15 | S 15 | S 14 | S 14 | S 14 | S 13 | S 13 | S 13 | S 12 | S 13 | S 13 | ENE 11 | S 13 | ENE 12 |
222 | 269 | 299 | 289 | 741 | 1178 | 1004 | 784 | 743 | 598 | 496 | 394 | 345 | 280 | 219 | 193 | 157 | 219 | 1447 | 114 | 3156 | |
Swell 2 Height (m) Direction Period (s) | SE 9 | SE 9 | S 20 | S 18 | SSW 13 | SE 9 | WNW 12 | SE 9 | SE 9 | SE 12 | SE 12 | SE 13 | SE 12 | E 11 | S 18 | S 17 | S 16 | S 16 | S 14 | S 15 | S 14 |
41 | 39 | 373 | 515 | 289 | 30 | 27 | 13 | 14 | 21 | 48 | 59 | 47 | 65 | 98 | 142 | 183 | 125 | 334 | 109 | 232 | |
Swell 3 Height (m) Direction Period (s) | S 11 | SSW 11 | SE 9 | SE 9 | SE 9 | W 12 | SW 19 | W 11 | W 12 | W 12 | W 11 | W 11 | W 13 | SE 12 | SE 12 | WNW 12 | WNW 11 | SE 12 | SE 11 | SE 11 | WNW 13 |
62 | 41 | 38 | 36 | 36 | 25 | 14 | 23 | 10 | 11 | 22 | 21 | 29 | 51 | 52 | 47 | 41 | 34 | 31 | 30 | 58 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | E 6 | ENE 7 | ENE 6 | ENE 6 | ENE 7 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 9 | ENE 10 | ENE 11 | ENE 11 | ENE 11 | ENE 11 | ENE 12 | — |
114 | 151 | 151 | 131 | 144 | 160 | 175 | 149 | 260 | 310 | 305 | 366 | 428 | 482 | 942 | 1249 | 1194 | 1230 | 1035 | 2164 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 31 | 16 | 31 | 16 | 16 | 16 | 31 | 16 | 31 | 31 | 16 | 31 | 31 | 31 | 31 | 31 | 31 | 126 | 126 | 126 |
Best forecast wave conditions in Kaua'i | |||||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||||
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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











