
Surf Forecasts:
Ammonias surf forecast from 12 Sep 2026:
- Most powerful swell: Thursday 17 Sep, 11PM (local time) - 3.5ft (1.0m), 18s period, SSW swell with 659 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 1.0m 18s 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) | 3.5ft (1.0m) 18s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, Rusty here, let’s chew the fat on what’s coming up for Ammonias over the next couple of weeks.
Honestly, it’s a pretty tough outlook for this reef setup. There’s a long, frustrating gap at the start. We’re talking about a stretch of six days, from Friday the 11th right through to Wednesday the 16th, where conditions are just not good – mostly poor surf and choppy, cross-onshore winds. There’s a bit of energy from a long-period groundswell on the 15th, around 2ft from the SW, but the wind messes it up. You’d be wasting your time.
Things start to look a little more interesting around Wednesday afternoon the 16th, with a bit more energy in the water (combined energy of 810), but it’s still a marginal call with a moderate cross-shore chop. The best bet in this whole window looks to be Thursday the 17th. You’ve got a bump in swell from the ENE, pushing 7ft in the morning and holding at 6ft in the afternoon. The period is short though, only 8 seconds, so it’ll be a bit soft and lumpy. The wind is cross-shore from the NE at 12 mph, so it’s not ideal, but it’s the most size you’ll see. The combined energy is strong at 933 in the morning and 1011 in the afternoon, but this is really only for experienced surfers; 7ft with that short period can be a handful and is too big for beginners.
After that, Friday the 18th has an interesting spike in energy (1210) from a SSW groundswell, but the swell drops to 3ft, so it’s all just power with less height. The wind is still cross-shore, keeping things average. Crowds at Ammonias are often an issue, so with the lack of quality, it might be a quiet one.
Looking further out, into the last week of September, the pattern doesn’t improve much. There’s a flash on Wednesday the 24th with 5ft from the E and a moderate cross-shore wind, but the energy is a bit messy. Friday the 25th afternoon shows an offshore wind from the SSE at just 3 mph, which is a big positive, and the swell is 5ft from the E. That could clean up nicely if it connects, but the period is short at 8 seconds and the overall energy is moderate (531). It’s a potential standout for the second week, but it’s a long ways out and less certain.
Water temperature is 80°F, pretty much average for this time of year, so no wetsuit needed.
So, to sum it up for you: Thursday the 17th is your best shot for size, and keep an eye on Friday the 25th afternoon for a possible clean but small window. Otherwise, it’s a long wait.
Rusty.
Short Range ForecastMostly dry. Warm (max 26°C on Fri afternoon, min 23°C on Sun night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 2mm), mostly falling on Tue night. Warm (max 27°C on Tue afternoon, min 24°C on Mon night). Wind will be generally light. | |||||||||||||||||||
Fri 11 | Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | ||||||||||||||
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 | ENE 11 | ENE 10 | ENE 10 | SSW 13 | ENE 9 | SSW 15 | SW 14 | SW 14 | SW 22 | SW 21 | SW 20 | SW 19 | SSW 19 | SW 18 | SSW 18 | SSW 17 | ENE 8 | ENE 8 | SSW 18 |
Wave Graph | ||||||||||||||||||||
229 | 379 | 163 | 160 | 98 | 84 | 84 | 99 | 49 | 227 | 224 | 392 | 384 | 465 | 449 | 541 | 360 | 449 | 395 | 651 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross-on | cross | cross | cross-on | cross | cross | cross | cross | cross | cross | cross | cross |
High Tide | 3:51PM0.55m | 4:29AM0.51m | 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 | |||||||||
Low Tide | 10:06PM0.05m | 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 | |||||||||
— | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:24 | — | — | 6:24 | — | — | 6:24 | — | — | |
6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — | — | — | — | — | — |
Temp °C | 26 | 25 | 26 | 25 | 25 | 26 | 25 | 25 | 26 | 26 | 25 | 26 | 27 | 25 | 27 | 27 | 26 | 27 | 27 | 26 |
Feels °C | 26 | 26 | 27 | 25 | 26 | 27 | 26 | 26 | 26 | 26 | 25 | 27 | 28 | 26 | 28 | 27 | 27 | 28 | 27 | 27 |
Swell 1 Height (m) Direction Period (s) | SW 15 | SW 15 | NE 9 | NE 9 | NE 9 | NE 9 | NE 9 | NE 9 | NE 8 | NE 8 | NE 8 | SW 20 | SW 19 | SSW 19 | SW 18 | SSW 18 | SSW 17 | SW 16 | SSW 16 | SSW 18 |
229 | 226 | 75 | 99 | 115 | 115 | 115 | 115 | 102 | 82 | 69 | 392 | 384 | 465 | 449 | 541 | 360 | 258 | 326 | 651 | |
Swell 2 Height (m) Direction Period (s) | SE 9 | SE 8 | SW 16 | SSW 16 | ENE 9 | SSW 15 | SSW 15 | SW 14 | SW 14 | SW 22 | SW 21 | NNE 8 | SW 12 | E 11 | NNE 7 | E 11 | E 11 | SSW 19 | E 10 | SSE 10 |
38 | 17 | 124 | 99 | 49 | 84 | 84 | 99 | 49 | 227 | 224 | 25 | 38 | 39 | 36 | 57 | 79 | 214 | 76 | 11 | |
Swell 3 Height (m) Direction Period (s) | SSW 12 | SE 6 | SSW 13 | SSW 13 | SSW 13 | SW 12 | ENE 9 | ENE 9 | SE 8 | SE 8 | SSW 13 | SW 12 | E 12 | SW 12 | E 11 | SW 11 | SE 8 | SSE 11 | SSW 19 | W 10 |
45 | 9 | 70 | 69 | 98 | 23 | 26 | 15 | 17 | 16 | 67 | 39 | 26 | 37 | 58 | 31 | 17 | 12 | 214 | 7 | |
Wind waves Height (m) Direction Period (s) | ENE 8 | ENE 11 | ENE 10 | ENE 10 | ENE 5 | ENE 9 | ENE 4 | E 5 | E 4 | ENE 4 | ENE 5 | ENE 8 | NE 8 | ENE 6 | ENE 6 | ENE 6 | ENE 7 | ENE 8 | ENE 8 | ENE 10 |
226 | 379 | 163 | 160 | 28 | 84 | 12 | 15 | 18 | 15 | 23 | 98 | 135 | 97 | 85 | 181 | 233 | 449 | 395 | 640 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 31 | 16 | 31 | 12 | 12 | 15 | 12 | 16 | 31 | 31 | 16 | 31 | 31 | 16 | 31 | 16 | 16 | 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










