
Surf Forecasts:
Ammonias surf forecast from 3 Sep 2026:
- Best quality surf: Monday 7 Sep, 2PM (local time) - 18ft (5.5m), 16s period, S swell with cross-onshore winds.
- Most powerful swell: Monday 7 Sep, 5PM (local time) - 38ft (11.5m), 15s period, S swell with 61,778 kJ wave energy.
- Next surfable swell (1★+): Monday 7 Sep, 2PM (local time) - 18ft (5.5m), 16s period with S 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 Monday (Sep 07) at 2PM. The primary swell is predicted to be 5.5m and 16s period with a secondary swell of 4.5m and 8s. The wind is predicted to be cross-onshore as the swell arrives.
The most powerful waves expected at Ammonias in the next 16 days are 11.5m 15s and forecast to arrive on Monday (Sep 07) at 5PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 7s period and expected on Tuesday (Sep 08) at 5AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2PM (Mon 7th Sep) | 18ft (5.5m) 16s |
| Best Surf | 2PM (Mon 7th Sep) | 18ft (5.5m) 16s |
| Most Powerful | 5PM (Mon 7th Sep) | 38ft (11.5m) 15s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s talk about what’s on offer for Ammonias.
Honestly, the next few days at Ammonias are going to be a test of patience. For Thursday and Friday of this week, we've got knee-to-waist high swell, around 4ft to 5ft from the SE, but the wind is a cross-shore mess at 15 to 19 mph, making everything lumpy and choppy. The water's sitting at a warm 81°, but the wave energy is actually quite strong (1310 to 1272) despite the poor conditions. It’s not what you’d call surfable right now, so save your energy.
Saturday isn't much different, still that 5ft range with cross-shore wind. The energy picks up to 1596 to 1663, but it's still that same rough, lumpy ocean.
Then on Sunday, things get real heavy. The swell jumps to 8ft from the ENE, but the wind swings cross-onshore, and the energy rockets up to 3453. This is not your day. Monday gets even more intense, with a 34ft monster from the SSE, period of 15 seconds, and near gale-force winds at 37 mph. That's a terrifying 50324 wave energy value. Unless you're a world-class big wave charger with a jet ski, stay well away. That setup is way too big for any normal paddle session here.
By Tuesday the 8th, it drops back down to a more manageable 6ft from the ENE, but the wind is still cross-shore, and the surf looks marginal. The afternoon does improve slightly with a 3ft SSW groundswell (14-second period) and lighter wind, but it's still just okay, not great.
Wednesday the 9th sees the swell bottom out at 3ft, so the only thing worth getting in the water for is maybe a longboard if you have nothing else to do.
Looking further out, from the 10th to the 14th, we get a mixed bag. You'll see some waist to chest-high sets (5ft to 7ft), but the period drops to a short, weak 7-8 seconds, meaning the waves will be fat and lack punch. The wind remains a persistent cross or cross-onshore breeze. There’s one window on the afternoon of Sunday the 13th where we get a clean, cross-off wind, which is promising for a small, lined-up wave, but the energy is low (631).
The absolute best bet in this entire 16-day window is a toss-up, but if I had to pick one, it’s the Tuesday afternoon of the 8th. The swell is small (3ft) but it has a long 14-second SSW groundswell that will wrap in nicely. The wind is a gentle cross-shore, and while the wave energy is still strong (1251), it’s the most manageable and cleanest of the early days. Still, it’s a "diamond in the rough" kind of session, not a standout. For a real standout, look to the end of the second week. On Tuesday the 15th, we get a very long 21-second SSW groundswell, but it’s only 3ft. That long period means it’ll be super clean and have more push than the size suggests, but the on-shore wind from the ESE will mess up the surface. A real tease.
All in all, Ammonias is going through a rough patch. If you're desperate, the afternoon of the 8th is your only real shot before the big, blown-out swell hits, and then it's a long, marginal grind until the end of the window.
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Thu afternoon. Warm (max 27°C on Thu afternoon, min 24°C on Thu night). Mainly fresh winds. | Days 4-6 Weather SummaryHeavy rain (total 57mm), heaviest during Mon night. Warm (max 28°C on Tue afternoon, min 23°C on Sun night). Winds decreasing (gales from the SE on Mon night, calm by Tue night). | ||||||||||||||||||||
Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | |||||||||||||||
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) | ENE 8 | SE 12 | ENE 7 | SSE 12 | SSE 12 | SSE 12 | S 12 | ENE 14 | S 12 | ENE 13 | SSW 13 | SSW 14 | SSW 15 | S 15 | SW 9 | ENE 11 | ENE 10 | SSW 14 | SSW 14 | ENE 8 | ENE 7 |
Wave Graph | |||||||||||||||||||||
480 | 486 | 443 | 548 | 599 | 541 | 636 | 1519 | 1100 | 1872 | 1804 | 2573 | 6721 | 61778 | 2247 | 817 | 473 | 356 | 341 | 314 | 340 | |
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-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross | glassy | cross | cross-on | cross |
High Tide | 9:35AM0.57m | 10:57AM0.61m | 12:04PM0.65m | 11:37PM0.20m | 12:57PM0.68m | 00:45AM0.25m | 1:42PM0.69m | 1:36AM0.30m | 2:20PM0.68m | 2:21AM0.36m | 2:54PM0.66m | 3:04AM0.41m | |||||||||
Low Tide | 2:01AM0.05m | 3:24AM0.06m | 8:23PM0.17m | 8:30PM0.15m | 6:02AM0.04m | 8:46PM0.13m | 7:02AM0.02m | 9:05PM0.11m | 7:55AM0.03m | 9:25PM0.09m | |||||||||||
6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | |
— | 6:52 | — | — | 6:51 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | |
mm | — | 1 | 1 | — | — | 1 | — | — | 3 | 2 | 6 | 15 | 6 | 7 | 19 | 2 | — | — | — | — | 1 |
Temp °C | 26 | 27 | 25 | 25 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 27 | 27 | 28 | 27 | 27 | 27 | 26 |
Feels °C | 25 | 26 | 23 | 23 | 23 | 23 | 25 | 24 | 24 | 25 | 25 | 24 | 25 | 23 | 20 | 28 | 29 | 31 | 30 | 29 | 27 |
Swell 1 Height (m) Direction Period (s) | SE 13 | SE 12 | SSE 11 | SSE 12 | SSE 12 | SSE 12 | S 12 | S 12 | S 12 | SSW 13 | SSW 13 | SSW 14 | SSW 15 | ENE 10 | ENE 12 | ENE 11 | ENE 10 | ENE 9 | SSW 14 | SSW 13 | SSW 13 |
480 | 486 | 329 | 548 | 599 | 541 | 636 | 833 | 1100 | 1365 | 1804 | 2573 | 6721 | 464 | 1164 | 817 | 473 | 274 | 341 | 257 | 178 | |
Swell 2 Height (m) Direction Period (s) | S 14 | S 14 | E 12 | E 14 | E 14 | E 14 | E 14 | SSW 18 | E 14 | SSE 9 | N 10 | N 9 | — | — | SE 9 | S 9 | S 8 | SSW 14 | S 8 | E 13 | E 13 |
268 | 246 | 109 | 196 | 289 | 401 | 561 | 121 | 704 | 34 | 8 | 6 | — | — | 384 | 463 | 234 | 356 | 60 | 171 | 171 | |
Swell 3 Height (m) Direction Period (s) | E 13 | E 13 | S 13 | SSW 13 | WSW 13 | SSW 20 | SSW 18 | NNE 10 | N 11 | N 10 | SSE 9 | — | — | — | SSW 15 | SSW 15 | SSW 15 | S 8 | E 13 | S 8 | S 8 |
85 | 80 | 92 | 60 | 16 | 37 | 121 | 18 | 9 | 2 | 34 | — | — | — | 487 | 487 | 456 | 132 | 176 | 43 | 29 | |
Wind waves Height (m) Direction Period (s) | ENE 8 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 14 | ENE 7 | ENE 13 | ENE 12 | E 7 | ENE 8 | S 15 | SW 9 | — | — | — | ENE 8 | ENE 8 | ENE 7 |
477 | 397 | 443 | 376 | 376 | 394 | 330 | 1519 | 290 | 1872 | 1703 | 589 | 1558 | 61778 | 2247 | — | — | — | 299 | 314 | 340 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 31 | 31 | 31 | 33 | 16 | 31 | 33 | 16 | 33 | 118 | 46 | 300 | 297 | 314 | 32 | 11 | 0 | 12 | 31 | 31 |
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










