
Surf Forecasts:
Ammonias surf forecast from 12 Sep 2026:
- Most powerful swell: Thursday 17 Sep, 11PM (local time) - 6.5ft (2.0m), 9s period, ENE swell with 710 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 2.0m 9s and forecast to arrive on Thursday (Sep 17) at 11PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 8s period and expected on Tuesday (Sep 15) at 5PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 11PM (Thu 17th Sep) | 6.5ft (2.0m) 9s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
G’day, Rusty here.
Look, I’m not gonna sugarcoat it – this 16-day run for Ammonias is a real tough one. We’re starting on Saturday the 12th of September and, honestly, there’s just nothing to get excited about for a long, long stretch. The entire first week is a write-off. We’re looking at weak, short-period slop with a persistent cross-onshore wind that’s got the surface all chopped up. The water’s sitting at 80°, which is pretty much bang on average for this time of year, so no surprises there.
The first few days, Saturday the 12th through Tuesday the 15th, are all “poor surf conditions.” Swell heights barely tickle 3 ft, and the combined energy is weak to moderate, like 255 to 528. It’s just a messy, cross-onshore breeze making a mess of things. You’d be wasting your time.
We finally see a bit of a bump on Wednesday the 16th, with the swell sneaking up to 3 ft and a period of 18 seconds. The combined energy jumps up to 739, which is in the moderate range. But the wind is still cross-shore and a bit breezy at 25 km/h, so it’s only called “marginal.” It’s a tease, not a thrill.
Thursday the 17th gets a bit bigger, with swell pushing 6 ft, but the period drops to a pitiful 7-8 seconds. That’s just short-period, wind-affected junk, and the cross-shore wind is still 25 km/h. The energy hits 957, but with that windy, short-period mess, it’s not surfable. Definitely not for beginners at that size, but the quality is so poor that even experts would be frustrated. The setup looks more interesting for kite surfing than paddle surfing.
The pattern just repeats. Friday the 18th sees 3 ft swell with a decent 16-17 second period, and combined energy over 1000 – strong to very strong. But the wind is still cross-shore and moderate, keeping it marginal at best. There’s a bit of a window that afternoon where it’s truly cross-shore, but it’s still messy.
From Saturday the 19th right through to the end on Sunday the 27th, it’s a blur of “poor” and “marginal” calls. The swell direction swings around, mostly from the SSW or ENE, and the wind never cleans up. The wave energy bounces between 500 and 900, but the conditions just don't come together. The swell starts to push over 5 ft again from the 21st to the 23rd, but it’s short-period stuff again, with a 7-10 second range, and the wind is always cross-onshore or cross.
There isn’t a single standout session in this entire forecast. The only day that even hinted at being okay was Wednesday the 16th afternoon, but even that was barely surfable. For Ammonias, this is a long, dry, frustrating stretch. Sometimes it’s just like this – the conditions don’t line up, and you’ve got to sit it out.
Later, Rusty.
Short Range ForecastMostly dry. Warm (max 26°C on Sat morning, min 24°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 9mm), mostly falling on Tue night. Warm (max 27°C on Tue afternoon, min 24°C on Tue morning). Wind will be generally light. | ||||||||||||||||||||
Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | |||||||||||||||
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 10 | ENE 10 | SSW 13 | SW 15 | ENE 9 | SW 14 | SW 14 | SW 22 | SW 21 | SW 20 | SW 19 | SSW 19 | SSW 18 | SSW 18 | SSW 17 | ENE 7 | ENE 8 | SSW 18 | SSW 17 | SSW 16 | SSW 16 |
Wave Graph | |||||||||||||||||||||
131 | 128 | 98 | 104 | 84 | 99 | 49 | 227 | 224 | 392 | 384 | 465 | 395 | 541 | 360 | 358 | 408 | 688 | 608 | 566 | 532 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross-on | cross-on | cross | cross-on | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross |
High Tide | 4:16PM0.48m | 5:11AM0.54m | 4:38PM0.41m | 5:56AM0.55m | 4:55PM0.35m | 6:45AM0.55m | 4:58PM0.30m | 7:44AM0.54m | 9:00AM0.53m | 10:23AM0.54m | 9:42PM0.19m | ||||||||||
Low Tide | 10:19AM0.13m | 10:28PM0.04m | 11:10AM0.18m | 10:50PM0.04m | 12:08PM0.22m | 11:14PM0.05m | 1:23PM0.26m | 11:40PM0.08m | 00:11AM0.10m | 00:58AM0.13m | 9:18PM0.19m | ||||||||||
6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:24 | — | — | 6:24 | — | — | 6:24 | — | — | 6:24 | — | — | |
— | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:37 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | 3 | — | — | 3 | 2 | — | 1 | 1 | — | 1 |
Temp °C | 26 | 26 | 25 | 26 | 25 | 25 | 26 | 26 | 25 | 26 | 27 | 26 | 26 | 27 | 26 | 26 | 27 | 25 | 26 | 27 | 26 |
Feels °C | 27 | 27 | 26 | 27 | 26 | 26 | 27 | 27 | 25 | 27 | 28 | 28 | 26 | 28 | 27 | 26 | 27 | 25 | 26 | 27 | 27 |
Swell 1 Height (m) Direction Period (s) | ENE 10 | NE 9 | NE 9 | NE 9 | NE 9 | NE 9 | NE 8 | SW 22 | NE 8 | SW 20 | SW 19 | SSW 19 | SSW 18 | SSW 18 | SSW 17 | SW 16 | SSW 16 | SSW 18 | SSW 17 | SSW 16 | SSW 16 |
131 | 120 | 115 | 115 | 115 | 115 | 102 | 227 | 69 | 392 | 384 | 465 | 395 | 541 | 360 | 258 | 326 | 651 | 608 | 566 | 532 | |
Swell 2 Height (m) Direction Period (s) | NE 9 | SSW 16 | ENE 9 | SW 15 | SSW 15 | SW 14 | SW 14 | SW 14 | SW 21 | NNE 8 | SW 12 | NNE 8 | E 11 | E 10 | E 10 | SSW 19 | SSW 19 | SSE 10 | SSE 10 | SSE 10 | SE 8 |
75 | 99 | 49 | 104 | 84 | 99 | 49 | 47 | 224 | 23 | 38 | 39 | 35 | 31 | 31 | 214 | 214 | 10 | 9 | 9 | 31 | |
Swell 3 Height (m) Direction Period (s) | SW 16 | SSW 13 | SSW 13 | SW 12 | SE 9 | ENE 9 | SE 8 | SE 8 | SW 13 | SSE 8 | E 12 | E 11 | SW 11 | SW 11 | SSW 21 | SE 8 | WSW 10 | W 10 | W 9 | W 9 | NE 7 |
124 | 69 | 98 | 23 | 21 | 15 | 17 | 16 | 44 | 11 | 26 | 39 | 33 | 31 | 86 | 11 | 9 | 2 | 6 | 6 | 12 | |
Wind waves Height (m) Direction Period (s) | — | ENE 10 | E 4 | ENE 9 | ENE 9 | E 5 | ENE 4 | ENE 8 | E 5 | ENE 8 | NE 8 | ENE 5 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 8 | ENE 9 | ENE 9 | ENE 9 | E 8 |
— | 128 | 18 | 64 | 82 | 27 | 18 | 212 | 31 | 125 | 140 | 62 | 111 | 136 | 237 | 358 | 408 | 688 | 488 | 453 | 331 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 12 | 12 | 14 | 12 | 16 | 31 | 31 | 16 | 31 | 31 | 16 | 16 | 31 | 16 | 31 | 31 | 15 | 16 | 16 | 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










