Surf Forecasts:
Ammonias surf forecast from 31 Aug 2026:
- Most powerful swell: Sunday 6 Sep, 11AM (local time) - 7ft (2.1m), 12s period, ENE swell with 1,261 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 2.1m 12s and forecast to arrive on Sunday (Sep 06) at 11AM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 11AM (Sun 6th Sep) | 7ft (2.1m) 12s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, let’s look at what’s cooking. It’s a rough run for the next couple of weeks. There’s swell, but the wind is almost never on your side. It’s mostly short-period windswell, with a side-shore or onshore breeze messing things up. A long stretch of poor conditions before we get a real window.
From Sunday the 30th of August right through to the morning of Wednesday the 2nd of September, it’s a bust. The swell is bumpy, the wind is cross or cross-on, and the energy is weak to moderate (637 to 904). The water is 27°, which is dead average for this time of year, but the waves are a mess.
We hit a terrible patch from the 3rd of September through the 5th. The swell gets bigger, to 2.4m to 3.0m from the ENE, but it’s under a fresh 30 to 35 km/h cross-onshore wind. The energy is climbing (1184 to 1933), but it’s unsurfable. For a reef break, that’s a total loss. You’d want a kite for this, not a surfboard.
The 6th and 7th of September are a step up, but still only marginal. The wind eases to a moderate cross-shore, and the swell holds around 2.0m to 2.5m from the ENE. The period stretches to 12 seconds on the afternoon of the 6th, giving it real groundswell power, and the energy jumps (1365 to 2565). It’s not clean, but there’s more punch.
The real highlight is Tuesday the 8th of September. The morning is wild, with 5.0m of E swell on a 10-second period, and the energy is huge (4805). That is a lot of water moving. But the afternoon is the best of the whole forecast. The wind swings to the N at 25 km/h, turning cross-offshore, and the wave condition says "clean." This is the only time everything lines up. The swell is a massive 5.0m from the E, so this is for experts only. It’s going to be a heavy, powerful day at Ammonias, and the energy is off the charts (5108). This is the window to wait for.
The 9th of September is still okay, with 3.0m of ENE swell, but the wind is light and cross. The energy drops a lot (1471 to 1694). It’s a step down from the day before, but still surfable.
After that, it’s a slow fade into small, wind-affected surf for the rest of the second week. The swell drops below 2.0m, the period shortens back to 8 seconds, and the wind is onshore or cross-onshore. From the 10th of September right through to the 14th, it’s just not worth it. The energy falls to between 500 and 895, and the conditions are lumpy or choppy. A real flat, frustrating end to the outlook.
So, for the experts, you’re waiting for the afternoon of Tuesday the 8th of September. That’s the only real standout. For everyone else, it’s a long, quiet wait.
- Rusty
Short Range ForecastLight rain (total 8mm), mostly falling on Sun night. Warm (max 27°C on Sun afternoon, min 25°C on Sun night). Wind will be generally light. | Days 5-7 Weather SummaryModerate rain (total 17mm), heaviest on Sat morning. Warm (max 27°C on Wed afternoon, min 25°C on Wed night). Mainly fresh winds. | |||||||||||||||||||
Sun 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | ||||||||||||||
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) | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | S 16 | S 16 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 |
Wave Graph | ||||||||||||||||||||
334 | 321 | 405 | 362 | 439 | 421 | 432 | 520 | 427 | 414 | 489 | 640 | 749 | 763 | 889 | 889 | 995 | 1145 | 908 | 720 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | cross | cross | cross | cross | cross-on | cross-on | cross-on | cross-on |
High Tide | 4:47PM0.49m | 5:58AM0.49m | 5:08PM0.42m | 6:57AM0.52m | 5:24PM0.35m | 8:09AM0.55m | 5:17PM0.30m | 9:35AM0.57m | 10:57AM0.61m | 12:04PM0.65m | 11:37PM0.20m | |||||||||
Low Tide | 11:17PM0.04m | 11:48AM0.20m | 11:45PM0.03m | 1:02PM0.26m | 00:18AM0.03m | 3:05PM0.29m | 1:01AM0.04m | 2:01AM0.05m | 3:24AM0.06m | 8:23PM0.17m | ||||||||||
— | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | |
6:54 | — | — | 6:54 | — | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — | — | 6:50 | — | |
mm | — | 2 | 2 | 1 | 1 | — | 1 | 1 | — | — | 2 | 2 | 1 | — | 1 | — | 3 | 8 | 8 | 8 |
Temp °C | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 27 | 26 | 26 | 26 | 25 | 25 | 25 | 25 | 26 | 26 | 26 |
Feels °C | 26 | 25 | 25 | 25 | 24 | 25 | 25 | 24 | 26 | 27 | 26 | 24 | 24 | 23 | 22 | 22 | 23 | 25 | 25 | 26 |
Swell 1 Height (m) Direction Period (s) | S 12 | SSW 15 | SSW 15 | S 11 | SSW 19 | S 18 | S 18 | S 17 | S 16 | S 16 | S 15 | S 14 | SE 13 | SE 12 | SE 11 | SE 11 | SSE 11 | SSE 10 | S 9 | SSE 7 |
100 | 196 | 191 | 82 | 391 | 314 | 314 | 373 | 427 | 406 | 352 | 268 | 330 | 409 | 488 | 485 | 582 | 463 | 568 | 120 | |
Swell 2 Height (m) Direction Period (s) | SSW 16 | S 11 | S 11 | SSW 14 | S 10 | SSW 14 | S 12 | SSE 10 | S 10 | S 10 | S 11 | SE 14 | S 14 | S 13 | S 13 | S 13 | E 13 | S 13 | E 13 | SSW 8 |
162 | 89 | 82 | 180 | 74 | 115 | 105 | 34 | 53 | 54 | 61 | 192 | 243 | 176 | 128 | 87 | 167 | 156 | 336 | 122 | |
Swell 3 Height (m) Direction Period (s) | ENE 11 | ENE 11 | ENE 10 | ENE 10 | SW 14 | S 9 | SW 14 | SW 14 | SSW 13 | E 14 | E 13 | E 13 | E 13 | E 12 | E 14 | E 14 | SSW 20 | SSW 18 | SSW 18 | E 13 |
41 | 40 | 33 | 33 | 52 | 45 | 53 | 52 | 17 | 37 | 56 | 84 | 78 | 47 | 59 | 93 | 37 | 123 | 121 | 268 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 |
334 | 321 | 405 | 362 | 439 | 421 | 432 | 520 | 392 | 414 | 489 | 640 | 749 | 763 | 889 | 889 | 995 | 1145 | 908 | 720 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 46 | 16 | 31 | 16 | 16 | 16 | 31 | 16 | 16 | 16 | 16 | 33 | 31 | 31 | 31 | 299 | 299 | 118 | 118 | 118 |
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











