
Surf Forecasts:
Ammonias surf forecast from 9 Sep 2026:
- Best quality surf: Tuesday 8 Sep, 11PM (local time) - 5.5ft (1.7m), 11s period, ENE swell with cross-offshore winds.
- Most powerful swell: Tuesday 8 Sep, 11PM (local time) - 5.5ft (1.7m), 11s period, ENE swell with 724 kJ wave energy.
- Next surfable swell (1★+): Tuesday 8 Sep, 11PM (local time) - 5.5ft (1.7m), 11s 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 Tuesday (Sep 08) at 11PM. The primary swell is predicted to be 1.7m and 11s period with a secondary swell of 1.4m 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 1.7m 11s and forecast to arrive on Tuesday (Sep 08) at 11PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 9s period and expected on Sunday (Sep 13) at 11PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Tue 8th Sep) | 5.5ft (1.7m) 11s |
| Best Surf | 11PM (Tue 8th Sep) | 5.5ft (1.7m) 11s |
| Most Powerful | 11PM (Tue 8th Sep) | 5.5ft (1.7m) 11s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s have a look at what’s coming down the pipe for the next 16 days.
Honestly, for the first week it’s a bit of a flat, messy picture. We’ve got some energy coming in, but the wind and conditions are fighting us every step of the way. The real standout, and really the only one worth getting excited about, lands on Tuesday afternoon of the 8th of September at Ammonias, a reef break. That afternoon we see a solid 6ft swell pushing in from the ENE, with a period of 11 seconds. Combined swell energy is strong at 1942. The water temperature is sitting at 80°, which is just about average for the time of year, so no surprises there. The wind is a cross-shore from the SW at 16 mph, which creates a cross-chop on the surface. It’s not glassy, but it’s rideable for an intermediate. Because it’s a reef break, the long-period swell (over 11 seconds) can really line up nicely here, but the crowd factor is listed as ‘often’, so expect plenty of company in the water.
After that, the outlook gets grim. There’s a long stretch of poor conditions and marginal surf from the 9th right through to the 18th of September. The wind keeps swinging cross-on or onshore, with speeds mostly between 9 and 16 mph, and the swell heights drop off quickly. On Wednesday the 9th, you’ve got a tiny 3ft swell from the SSW, but it’s onshore and weak. Thursday the 10th brings a short, choppy 5ft to 6ft ENE swell with periods under 8 seconds – not going to hold up at a reef. The rest of that run is consistently poor, with energy readings below 1000 and a lot of chop.
Things start to look a little more hopeful by Friday the 18th of September. The morning swings into a cross-shore wind from the ENE, 12 mph, with a 3ft SSW swell at a promising 17 seconds. The combined energy nudges up into moderate territory at 1018. The light cross-shore breeze will keep the face fairly clean, and the long period means the reef will produce some good-shaped, grunty waves. It’s still marginal for quality, but by far the best we’ve seen in over a week. Expect the crowd factor to be ‘often’ – it’s a quality slab, so it draws attention.
The rest of the second week sees the swell fade back again. We’re into small, weak waves from the SSW with periods in the 13 to 15-second range, and the wind stays mostly cross-shore. There’s no second standout in the window. The conditions just don’t come together again.
So, to sum it up: if you want the best of a dodgy run, Tuesday, 8th of September at Ammonias is your call. It’s not perfect, but it’s the biggest and most energetic of the lot. The Friday, 18th of September morning offers a cleaner, longer-period option if you’re patient and can handle the crowds. For everything else, it’s a waiting game.
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Tue afternoon. Warm (max 28°C on Wed afternoon, min 24°C on Thu night). Winds decreasing (fresh winds from the SW on Tue afternoon, calm by Wed night). | Days 5-7 Weather SummaryLight rain (total 5mm), mostly falling on Sat night. Warm (max 26°C on Fri afternoon, min 24°C on Fri night). Wind will be generally light. | |||||||||||||||||||
Tue 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | Monday 14 | ||||||||||||||
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 11 | ENE 11 | SSW 14 | SSW 13 | SSW 13 | ENE 8 | ENE 7 | ENE 7 | SW 16 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | SSW 13 | SSW 15 | SSW 14 | SSW 14 | SW 23 | SW 22 | SW 21 |
Wave Graph | ||||||||||||||||||||
771 | 560 | 336 | 253 | 178 | 296 | 314 | 227 | 198 | 331 | 436 | 163 | 125 | 98 | 84 | 82 | 78 | 138 | 227 | 224 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross-on | on | cross | cross-on | cross-on | cross | cross-on | cross | cross-on | cross-on | cross-on | cross | cross-on | cross-on | cross | cross | cross | cross |
High Tide | 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 | 5:11AM0.54m | 4:38PM0.41m | 5:56AM0.55m | 4:55PM0.35m | |||||||
Low Tide | 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 | 11:10AM0.18m | 10:50PM0.04m | 12:08PM0.22m | 11:14PM0.05m | |||||||
— | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | |
6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — | — | 6:43 | — | — | 6:42 | — | — | 6:40 | — | |
mm | 1 | — | — | — | — | 2 | 2 | 1 | — | — | — | — | 2 | 3 | — | — | — | — | — | — |
Temp °C | 27 | 26 | 27 | 28 | 26 | 27 | 26 | 25 | 26 | 26 | 25 | 25 | 25 | 25 | 26 | 26 | 25 | 26 | 26 | 26 |
Feels °C | 27 | 29 | 30 | 31 | 30 | 29 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 27 | 27 | 28 | 26 | 27 | 27 | 28 |
Swell 1 Height (m) Direction Period (s) | ENE 11 | ENE 11 | ENE 10 | ENE 9 | ENE 8 | SSW 13 | SSW 12 | SW 16 | SW 16 | SW 15 | SW 15 | ENE 10 | ENE 10 | NE 9 | NE 9 | NE 9 | NE 9 | SE 8 | SW 22 | NE 8 |
771 | 560 | 264 | 194 | 136 | 173 | 172 | 211 | 198 | 229 | 223 | 163 | 125 | 91 | 88 | 93 | 95 | 18 | 227 | 54 | |
Swell 2 Height (m) Direction Period (s) | SSW 14 | S 8 | SSW 14 | SSW 13 | SSW 13 | E 12 | E 12 | SSW 12 | E 11 | NNE 8 | SE 8 | NE 8 | NE 9 | ENE 9 | ENE 9 | E 5 | SSW 14 | SW 14 | SE 8 | SW 21 |
449 | 182 | 336 | 253 | 178 | 108 | 104 | 81 | 91 | 39 | 18 | 69 | 79 | 48 | 64 | 14 | 78 | 49 | 17 | 224 | |
Swell 3 Height (m) Direction Period (s) | NW 9 | SSW 14 | S 8 | S 7 | E 13 | SSW 17 | SW 18 | E 12 | SSW 12 | SSW 12 | SSW 11 | SW 16 | SSW 16 | SSW 13 | SSW 15 | SSW 14 | SE 9 | SW 23 | SW 14 | SSW 13 |
62 | 431 | 74 | 54 | 119 | 186 | 154 | 99 | 79 | 45 | 23 | 124 | 99 | 98 | 84 | 82 | 20 | 138 | 47 | 67 | |
Wind waves Height (m) Direction Period (s) | SSW 8 | — | — | — | — | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 11 | ENE 11 | — | — | E 4 | — | — | ENE 6 | NE 8 | NE 8 | ENE 5 |
722 | — | — | — | — | 296 | 314 | 227 | 158 | 331 | 436 | — | — | 19 | — | — | 52 | 162 | 138 | 31 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 11 | 11 | 11 | 31 | 10 | 14 | 31 | 16 | 31 | 16 | 15 | 15 | 12 | 16 | 12 | 12 | 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










