Surf Forecasts:
Ammonias surf forecast from 6 Sep 2026:
- Best quality surf: Wednesday 9 Sep, 2AM (local time) - 5ft (1.6m), 10s period, ENE swell with cross-offshore winds.
- Most powerful swell: Monday 7 Sep, 11PM (local time) - 16ft (5.0m), 14s period, SSW swell with 9,663 kJ wave energy.
- Next surfable swell (1★+): Wednesday 9 Sep, 2AM (local time) - 5ft (1.6m), 10s 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 Wednesday (Sep 09) at 2AM. The primary swell is predicted to be 1.6m and 10s period with a secondary swell of 1.2m and 8s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Ammonias in the next 16 days are 5.0m 14s and forecast to arrive on Monday (Sep 07) at 11PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 2.1m 10s period and expected on Tuesday (Sep 08) at 11AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Wed 9th Sep) | 5ft (1.6m) 10s |
| Best Surf | 2AM (Wed 9th Sep) | 5ft (1.6m) 10s |
| Most Powerful | 11PM (Mon 7th Sep) | 16ft (5.0m) 14s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s get into it, surfers.
We’re looking at a 16-day stretch for Ammonias, and I gotta be straight with you – this isn’t a classic run at all. The first real chance for a paddle isn’t until very late in the game, so we’ve got a long wait ahead. There’s a big gap of nearly two weeks where the conditions are just too messy to recommend, with onshore winds and poor surf quality ruling the roost.
Ammonias is a reef setup that really wants swell from the SSE to light up, and it’s fairly consistent when it does. But for the first week and a half, we’re mostly seeing cross and cross-onshore winds, and the swell is either small, short-period, or coming from directions that don’t hit the spot. The water temp is sitting around 81°, which is pretty much spot-on average for this time of year – nothing unusual there.
Looking at Sunday the 8th of September, Tuesday morning we get a pulse of 8ft S swell with a short 9-second period, but it's messy with 16 mph cross winds. The afternoon settles a bit to 6ft from the ENE, but it’s still pretty marginal.
The only real bright spot – and I mean the *only* standout – comes much later. Check out Thursday the 17th of September and Friday the 18th of September. On Thursday, we’ve got a 7ft E swell showing up. It's a bit short-period at 8 seconds, but the wind is a light gentle breeze and it’s cross-on, not too ugly. The combined swell energy is moderate at 1123. Then Friday the 18th picks up again with a 7ft E swell, same short period, but the wind swings cross-shore with a moderate breeze, keeping things a little cleaner. The combined energy is still solid at 1119. After nearly two weeks of blank days, this is the best we’ve got. It’s not a world-beater, but for a reef that loves swell from the east, it’s worth checking if you’re desperate.
The rest of the run into Saturday the 20th and Monday the 21st has a bit of size, 7ft range, but it’s inconsistent and the period stays short, so expect a lot of close-outs. Honestly, for most of this window, the setup looks more interesting for a kite surfer than a paddle surfer, with that steady ENE wind and chop.
Hang in there, wait for that window around the 17th, and hope the forecasts hold. It’s been a quiet run.
Rusty.
Short Range ForecastHeavy rain (total 61mm), heaviest during Sun night. Warm (max 28°C on Tue afternoon, min 24°C on Sun night). Winds decreasing (near gales from the ESE on Mon night, calm by Tue night). | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Wed afternoon. Warm (max 28°C on Wed afternoon, min 24°C on Thu night). Wind will be generally light. | ||||||||||||||||||||
Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | |||||||||||||||
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 13 | ENE 12 | SSW 14 | SSW 14 | SSW 15 | SSW 13 | S 9 | ENE 11 | ENE 10 | SSW 14 | SSW 13 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | SSW 16 | ENE 7 | ENE 7 | ENE 11 | ENE 10 | ENE 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1521 | 1392 | 1683 | 2570 | 4347 | 7542 | 929 | 757 | 490 | 341 | 257 | 226 | 231 | 231 | 186 | 164 | 183 | 248 | 480 | 402 | 402 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross | cross-off | on | on | cross-on | cross-on | cross-on | cross | cross-on | cross | cross | cross | cross | cross |
High Tide | 12:57PM0.68m | 00:45AM0.25m | 1:42PM0.69m | 1:36AM0.30m | 2:20PM0.68m | 2:21AM0.36m | 2:54PM0.66m | 3:04AM0.41m | 3:24PM0.61m | 3:47AM0.47m | 3:51PM0.55m | 4:29AM0.51m | 4:16PM0.48m | ||||||||
Low Tide | 8:30PM0.15m | 6:02AM0.04m | 8:46PM0.13m | 7:02AM0.02m | 9:05PM0.11m | 7:55AM0.03m | 9:25PM0.09m | 8:43AM0.05m | 9:45PM0.07m | 9:31AM0.09m | 10:06PM0.05m | 10:19AM0.13m | 10:28PM0.04m | ||||||||
 | |  | | | |  |  |  | | |  | | |  |  | | | | | | |
 | 6:20 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — |
 | — | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — |
mm | 1 | 2 | 23 | 11 | 8 | 15 | 1 | — | — | — | 1 | 2 | — | 2 | — | — | — | — | — | — | 2 |
Temp °C | 26 | 26 | 26 | 25 | 26 | 27 | 27 | 28 | 26 | 27 | 28 | 27 | 26 | 26 | 26 | 25 | 26 | 25 | 26 | 26 | 25 |
Feels °C | 25 | 25 | 26 | 23 | 24 | 23 | 28 | 29 | 29 | 30 | 32 | 30 | 28 | 27 | 27 | 25 | 26 | 25 | 26 | 25 | 24 |
Swell 1 Height (m) Direction Period (s) | SSW 12 | SSW 12 | SSW 14 | SSW 14 | SSW 15 | SSW 13 | S 9 | ENE 11 | ENE 10 | ENE 9 | ENE 8 | SSW 13 | SSW 13 | SSW 12 | SSW 16 | E 12 | ENE 12 | SW 15 | SSW 16 | SSW 16 | SSW 13 |
| kJ | 486 | 718 | 1683 | 2570 | 4347 | 7542 | 929 | 757 | 490 | 255 | 147 | 178 | 173 | 121 | 175 | 137 | 142 | 226 | 99 | 99 | 67 |
Swell 2 Height (m) Direction Period (s) | SSW 16 | SSE 10 | E 12 | SSE 8 | E 12 | ENE 12 | W 10 | S 8 | S 8 | SSW 14 | SSW 13 | E 13 | E 12 | E 12 | E 12 | SSW 16 | SSW 15 | SSW 11 | SSW 13 | SW 13 | SW 16 |
| kJ | 382 | 38 | 472 | 164 | 613 | 1072 | 882 | 439 | 182 | 341 | 257 | 119 | 106 | 104 | 101 | 164 | 150 | 23 | 70 | 45 | 64 |
Swell 3 Height (m) Direction Period (s) | SSE 10 | SSW 19 | SSE 10 | NW 14 | NNW 13 | NW 12 | ENE 11 | W 9 | SSW 14 | S 8 | S 8 | S 8 | SSW 17 | SW 18 | SSW 12 | SSW 12 | SSW 12 | SE 8 | SE 8 | SE 8 | SE 8 |
| kJ | 36 | 122 | 38 | 8 | 17 | 6 | 759 | 293 | 356 | 82 | 57 | 42 | 186 | 154 | 82 | 79 | 46 | 18 | 17 | 10 | 9 |
Wind waves Height (m) Direction Period (s) | ENE 13 | ENE 12 | ENE 7 | ENE 7 | ESE 8 | SSE 8 | — | — | — | — | — | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 11 | ENE 10 | ENE 10 |
| kJ | 1521 | 1392 | 432 | 756 | 1535 | 897 | — | — | — | — | — | 226 | 231 | 231 | 186 | 158 | 183 | 248 | 480 | 402 | 402 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 31 | 118 | 303 | 231 | 249 | 32 | 11 | 0 | 45 | 16 | 14 | 31 | 31 | 16 | 31 | 16 | 16 | 31 | 31 | 16 |
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
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