
Surf Forecasts:
Ammonias surf forecast from 13 Sep 2026:
- Most powerful swell: Friday 18 Sep, 8AM (local time) - 7ft (2.1m), 9s period, E swell with 694 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 9s and forecast to arrive on Friday (Sep 18) at 8AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 8s period and expected on Tuesday (Sep 15) at 8PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 8AM (Fri 18th Sep) | 7ft (2.1m) 9s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s coming our way at Ammonias.
The next 16 days are looking pretty grim for decent surf. We’re starting off with a big gap of nothing. There isn’t a single recommendation for the first few days. The first time we even see a glimmer of hope is on Tuesday the 15th of September, and even then it’s a marginal call.
The overall pattern is messy. We’ve got swell coming in, but the wind is relentless from the east-northeast, blowing cross or cross-on, keeping things chopped up and ugly. The water temperature is about average for this time of year.
Let’s run through it. Sunday the 13th and Monday the 14th are write-offs. Poor conditions with tiny, weak swell and cross-onshore breeze.
Tuesday the 15th of September morning is the first time we get a marginal nod. Swell is only 2ft from the SW, but with a nice long period of 20 seconds. That long period means cleaner energy, but the combined energy is moderate at 535. The wind is still a gentle cross-shore, so there’s a slight cross-chop. It’s not good, but it’s the best on offer early on. If you’re desperate, you might find a clean-up set, but crowds are likely here, so don’t expect much.
Wednesday the 16th sees the swell bump up a little to 3ft from the SW, period at 18 seconds, and the combined energy climbs to a moderate 607. But that moderate breeze from the NE keeps it cross-shore and bumpy. Still marginal at best.
Then things get bigger but uglier. From Thursday the 17th through to the end of the outlook, we get a mix of easterly windswell and stormy conditions. Swell heights push over 7ft, but the period drops to a short, weak 7 to 10 seconds, and the wind stays onshore or cross-onshore. Thursday the 17th has a risk of thunderstorms and 6ft of short-period junk. By Friday the 18th, we’re looking at 7ft from the east with a period of just 9 seconds and moderate cross-onshore winds. That’s not surf, that’s a washing machine. The combined energy gets strong, hitting 1319, but it’s all messy windswell. For a reef setup like Ammonias, this is only for experts, and honestly, it’s more interesting for kite surfing than paddle surfing.
The pattern holds through the rest of the period. Big, lumpy, short-period swell with persistent cross-shore winds. There are a few marginal mornings, like Saturday the 26th of September with 7ft from the east, but the period is still only 8 seconds and the wind is cross-shore. You’re battling chop and no shape.
In short, the only half-decent window is Tuesday the 15th of September morning, and even that’s a stretch. The rest is a long, frustrating run of poor conditions. For an area like this, a blank run isn’t unusual, but it still stings.
Stay patient, mates. The ocean will sort itself out eventually.
Rusty.
Short Range ForecastMostly dry. Warm (max 26°C on Mon afternoon, min 24°C on Sat night). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 29mm), heaviest during Fri afternoon. Warm (max 27°C on Wed afternoon, min 25°C on Tue night). Wind will be generally light. | ||||||||||||||||||
Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | ||||||||||||||
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) | SSW 13 | SW 15 | SSW 15 | SW 14 | SW 14 | SW 22 | SW 21 | SW 20 | SW 19 | SW 19 | SW 18 | SSW 18 | SSW 17 | ENE 7 | ENE 7 | ENE 9 | E 9 | ENE 8 | ENE 8 |
Wave Graph | |||||||||||||||||||
98 | 104 | 84 | 99 | 49 | 227 | 224 | 392 | 384 | 372 | 449 | 541 | 360 | 319 | 379 | 662 | 678 | 566 | 532 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | cross | cross | cross | cross-on | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-on | cross-on |
High Tide | 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 | 10:28PM0.04m | 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 | — | — | 6:24 | — | — | 6:24 | — | — | 6:24 | — | — | 6:24 | — | — | |
6:43 | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:37 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | 3 | 2 | 2 | 6 | 6 | 10 | 6 |
Temp °C | 25 | 25 | 25 | 25 | 25 | 26 | 25 | 26 | 26 | 25 | 26 | 27 | 25 | 26 | 26 | 25 | 27 | 27 | 26 |
Feels °C | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 27 | 27 | 26 | 26 | 27 | 25 | 26 | 25 | 25 | 27 | 27 | 27 |
Swell 1 Height (m) Direction Period (s) | NE 9 | NE 9 | NE 9 | NE 9 | NE 8 | NE 8 | NE 8 | SW 20 | SW 19 | SW 19 | SW 18 | SSW 18 | SSW 17 | SW 16 | SSW 16 | SSW 18 | SSW 17 | SSW 16 | SSW 16 |
115 | 115 | 115 | 115 | 102 | 68 | 54 | 392 | 384 | 372 | 449 | 541 | 360 | 258 | 326 | 651 | 608 | 566 | 532 | |
Swell 2 Height (m) Direction Period (s) | ENE 9 | SW 15 | SSW 15 | SW 14 | SW 14 | SW 22 | SW 21 | NNE 8 | SW 12 | NNE 8 | E 11 | E 10 | E 10 | SSW 19 | SSW 19 | SSE 10 | S 21 | SE 7 | SSE 8 |
49 | 104 | 84 | 99 | 49 | 227 | 224 | 23 | 38 | 39 | 35 | 32 | 48 | 214 | 214 | 10 | 33 | 13 | 44 | |
Swell 3 Height (m) Direction Period (s) | SSW 13 | SW 12 | SE 9 | ENE 9 | SE 8 | SW 14 | SW 13 | SW 12 | E 12 | E 11 | SW 11 | SW 11 | SW 11 | SW 10 | SW 10 | W 10 | W 9 | S 21 | S 20 |
98 | 23 | 21 | 15 | 17 | 47 | 44 | 40 | 26 | 39 | 33 | 43 | 30 | 17 | 15 | 2 | 2 | 36 | 119 | |
Wind waves Height (m) Direction Period (s) | E 4 | ENE 9 | ENE 9 | E 4 | ENE 4 | ENE 5 | ENE 5 | ENE 8 | NE 8 | ENE 5 | ENE 6 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 9 | E 9 | ENE 8 | ENE 8 |
15 | 84 | 62 | 26 | 14 | 41 | 38 | 103 | 119 | 44 | 90 | 111 | 197 | 319 | 379 | 662 | 678 | 547 | 520 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 12 | 31 | 12 | 16 | 31 | 31 | 16 | 31 | 31 | 16 | 16 | 31 | 16 | 31 | 31 | 16 | 33 | 33 | 16 |
Best forecast wave conditions in Kaua'i | |||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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










