
Surf Forecasts:
Ammonias surf forecast from 2 Sep 2026:
- Most powerful swell: Tuesday 8 Sep, 11AM (local time) - 15ft (4.5m), 14s period, SSW swell with 7,863 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 4.5m 14s and forecast to arrive on Tuesday (Sep 08) at 11AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 9s period and expected on Saturday (Sep 05) at 11PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 11AM (Tue 8th Sep) | 15ft (4.5m) 14s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, Rusty here, let's get into it.
Alright, things are looking pretty grim at Ammonias for the next 16 days. This is a reef break that's fairly consistent, but we're battling a rough stretch of weather and wind. The first recommendation doesn't even roll around until Thursday morning, the 3rd of September, with only a marginal look.
The problem is the wind. For the first 10 days, we've got a persistent cross-shore or cross-onshore breeze out of the ENE and NE, blowing 12 to 19 mph. That's going to chop everything up. The water temp is about average for the time of year, so nothing weird there.
The swell energy picks up significantly from the 4th through the 8th, with combined energy readings in the thousands (1437 to 9083), so there's definitely power out there on offer, but the wind is just ruining the ride. The swell is coming from the S, SSE, and ENE, with a 12 to 14-second period on that southerly groundswell. That longer period is better for shaping, but it's going to be straight and messy at a beach setup. When that SSE groundswell fills in on Friday the 4th, it'll be 5 ft, but those fresh cross-shore winds will make it lumpy as hell. The 15 ft swell on Tuesday the 8th is only for experts if it even breaks, but with a 28 mph onshore wind and a risk of thunderstorms, it's a session to skip. That setup looks more interesting for kite surfing than paddle surfing in those conditions.
The only real glimmer of hope and the standout of the whole outlook is on the 16th of September, Wednesday morning. It's a late call, so I'd approach it with some caution, but it's the cleanest it will be. The wind drops right off to a light breeze from the E at 6 mph, creating just a light cross-onshore with small wind ripples. The swell eases to 4 ft from the SW with a very long period of 18 seconds. That's pure groundswell energy humming in at 1062 on the energy scale. At a reef break, that long period will wrap in nicely, giving you proper shape and long, clean lines. It won't be huge, but it will be the most surfable wave we've seen in two weeks. Crowds are a concern as this spot can get crowded, but that's a risk you'll have to take for the best of a bad run.
There's also a shout-out to Monday the 14th. You've got a 6 ft S swell with a 10-second period in the morning. It's still a cross-shore, but only a gentle breeze at 9 mph, which is manageable. The energy is decent at 1083, and it could be alright for a paddle. But the real gem is that Wednesday the 16th.
A blank run like this is pretty normal for the spot when the trade winds lock in. Don't take a risk on the big, stormy days. Wait for that window.
- Rusty
Short Range ForecastModerate rain (total 15mm), heaviest on Wed morning. Warm (max 26°C on Wed morning, min 25°C on Tue night). Mainly fresh winds. | Days 5-7 Weather SummaryHeavy rain (total 29mm), heaviest during Sun night. Warm (max 26°C on Sat morning, min 23°C on Mon morning). Wind will be generally light. | ||||||||||||||||||
Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | ||||||||||||||
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 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | SE 12 | SSE 12 | SSE 12 | SSE 12 | SSE 12 | S 12 | ENE 13 | ENE 13 | ENE 13 | ENE 13 | ENE 12 | ENE 13 | SSW 14 | SSW 15 |
Wave Graph | |||||||||||||||||||
463 | 582 | 515 | 460 | 509 | 522 | 626 | 655 | 559 | 541 | 710 | 1679 | 1831 | 1605 | 1532 | 1428 | 1864 | 2002 | 4648 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | on | cross | cross-on |
High Tide | 8:09AM0.55m | 5:17PM0.30m | 9:35AM0.57m | 10:57AM0.61m | 12:04PM0.65m | 11:37PM0.20m | 12:57PM0.68m | 00:45AM0.25m | 1:42PM0.69m | 1:36AM0.30m | |||||||||
Low Tide | 00:18AM0.03m | 3:05PM0.29m | 1:01AM0.04m | 2:01AM0.05m | 3:24AM0.06m | 8:23PM0.17m | 8:30PM0.15m | 6:02AM0.04m | 8:46PM0.13m | ||||||||||
— | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:22 | — | — | |
6:53 | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | |
mm | 4 | 3 | 3 | 2 | 1 | 1 | 1 | — | — | — | — | 1 | 4 | 2 | 2 | 10 | 6 | 4 | 5 |
Temp °C | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 24 | 24 | 26 |
Feels °C | 25 | 26 | 26 | 25 | 25 | 24 | 24 | 24 | 23 | 23 | 25 | 25 | 24 | 26 | 25 | 25 | 25 | 24 | 25 |
Swell 1 Height (m) Direction Period (s) | S 17 | S 16 | S 16 | S 15 | SE 12 | SE 12 | SSE 12 | SSE 12 | SSE 12 | SSE 12 | S 12 | S 12 | S 12 | SSW 12 | SSW 12 | SSW 12 | ENE 13 | SSW 14 | SSW 15 |
373 | 427 | 406 | 352 | 430 | 522 | 626 | 655 | 559 | 541 | 710 | 805 | 702 | 559 | 797 | 446 | 1864 | 2002 | 4648 | |
Swell 2 Height (m) Direction Period (s) | SSE 10 | S 10 | SSE 10 | SE 13 | S 14 | S 14 | E 12 | E 14 | E 14 | E 14 | E 14 | SSW 18 | SSW 16 | SSW 16 | SSE 10 | SSW 15 | SSW 14 | S 17 | NNW 12 |
34 | 53 | 31 | 176 | 264 | 189 | 109 | 196 | 289 | 395 | 538 | 121 | 147 | 229 | 38 | 443 | 1686 | 569 | 14 | |
Swell 3 Height (m) Direction Period (s) | SW 14 | SSW 13 | S 12 | S 11 | E 13 | E 13 | S 13 | SSW 13 | SSW 20 | SSW 20 | SSW 18 | NNE 10 | N 11 | SSE 10 | SSW 20 | SSW 18 | SSW 17 | NNW 13 | NW 12 |
52 | 17 | 25 | 58 | 85 | 80 | 92 | 60 | 38 | 37 | 121 | 18 | 2 | 35 | 127 | 348 | 487 | 17 | 37 | |
Wind waves Height (m) Direction Period (s) | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 7 | ENE 7 | ENE 13 | ENE 13 | ENE 13 | ENE 13 | ENE 12 | — | ENE 13 | ENE 12 |
463 | 582 | 515 | 460 | 509 | 440 | 512 | 526 | 495 | 390 | 353 | 1679 | 1831 | 1605 | 1532 | 1428 | — | 1872 | 2197 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 16 | 16 | 33 | 16 | 31 | 31 | 38 | 31 | 31 | 16 | 31 | 31 | 16 | 31 | 16 | 38 | 33 | 16 | 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










