
Surf Forecasts:
Ammonias surf forecast from 8 Aug 2026:
- Most powerful swell: Thursday 13 Aug, 2AM (local time) - 4.5ft (1.4m), 16s period, S swell with 1,029 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 1.4m 16s and forecast to arrive on Thursday (Aug 13) at 2AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 12s period and expected on Thursday (Aug 13) at 2AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 2AM (Thu 13th Aug) | 4.5ft (1.4m) 16s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get into it.
The next 16 days at Ammonias are a bit of a grind – there’s a lot of cross and cross-onshore wind messing things up, and the swell is mostly short-period, wind-affected stuff. The water temperature is sitting around 80°, which is basically normal for this time of year, so nothing weird going on there.
The first time we see any glimmer of hope is on the morning of Sunday, 11 August. The swell is still pretty poor at 5 ft from the ENE, but the period is a weak 7 seconds, so it’s just wind swell. The wind is cross-on, and the energy is moderate (471). It’s not really worth getting excited about.
Things start to look a little more interesting from Wednesday, 14 August, through to Friday, 16 August. On Wednesday the 14th, we get a new pulse of S swell with a long period of 18 seconds. That’s a proper groundswell, and the energy is strong (1013 on the morning, 1227 in the afternoon). But the direction is S, and the guidance says Ammonias prefers SSE swell, so it’s a bit off. The wind is cross, not clean. The waves are 3 ft to 4 ft – small, but with that long period, the shape could be fun if you look for a corner. It’s only marginal, but it’s the best we’ve got for a while.
Thursday the 15th morning is similar, with 5 ft S swell, period 16 seconds, and strong energy (1280). The wind is still cross from the NE at 16 mph. This is a stand-out option for the whole period – the swell is decent, the period is long, and the energy is solid. But the wind is the problem. If it backs off or goes a touch more offshore, it could clean up nicely. The swell is over 5 ft, so it’s getting a bit much for beginners, but fine for intermediates.
The standout for the whole 16 days comes on the morning of Thursday, 22 August. The swell is 10 ft from the ENE, with a period of 9 seconds. That’s strong energy (1961). But the wind is cross-on at 19 mph, and that’s too much chop for proper paddle surfing. With that size and wind, it’s more of a kite day. The swell is over 8 ft, so only for the experts. The period is short, so it’s not going to be clean.
After that, the swell drops off pretty quickly. By the end of the run, we’re back to small, messy south swells with no real quality.
So, the one true stand-out is the Thursday 15th through Friday 16th for that S groundswell – it’s the best combination of size, period, and energy, even with the cross wind. If you can find a corner that’s less affected, you’ll get a wave. The really big stuff on the 22nd is more of a windsurfing or kite show.
Rusty.
Short Range ForecastLight rain (total 7mm), mostly falling on Mon morning. Warm (max 26°C on Fri afternoon, min 24°C on Fri night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 4mm), mostly falling on Mon afternoon. Warm (max 27°C on Tue afternoon, min 24°C on Tue night). Wind will be generally light. | |||||||||||||||||||
Fri 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | ||||||||||||||
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) | SW 20 | SSW 19 | SSW 14 | SW 18 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | S 20 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 |
Wave Graph | ||||||||||||||||||||
98 | 148 | 156 | 167 | 212 | 219 | 218 | 263 | 259 | 234 | 231 | 188 | 210 | 373 | 515 | 741 | 1029 | 1004 | 784 | 743 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross-on | cross | cross | cross-on | cross | cross | cross-on | cross | cross-on | cross-on | cross-on | cross | cross | cross | cross | cross | cross | cross |
High Tide | 1:18PM0.69m | 00:17AM0.19m | 2:05PM0.73m | 1:24AM0.22m | 2:47PM0.75m | 2:17AM0.26m | 3:26PM0.74m | 3:06AM0.30m | 4:02PM0.71m | 3:54AM0.34m | 4:34PM0.66m | 4:44AM0.37m | ||||||||
Low Tide | 4:56AM-0.01m | 9:20PM0.16m | 6:02AM-0.03m | 9:35PM0.15m | 7:01AM-0.05m | 9:56PM0.13m | 7:54AM-0.06m | 10:20PM0.12m | 8:43AM-0.04m | 10:44PM0.10m | 9:30AM-0.00m | 11:09PM0.08m | ||||||||
— | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | |
7:13 | — | — | 7:13 | — | — | 7:12 | — | — | 7:10 | — | — | 7:10 | — | — | 7:09 | — | — | 7:08 | — | |
mm | — | 1 | 2 | — | — | — | — | 1 | 3 | 2 | 2 | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 27 | 25 | 26 | 26 | 25 | 27 | 27 | 25 |
Feels °C | 26 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 27 | 26 | 26 | 26 | 27 | 25 | 25 | 25 | 24 | 26 | 25 | 24 |
Swell 1 Height (m) Direction Period (s) | SSW 14 | SSW 14 | SSW 14 | SSW 13 | SSW 13 | SSW 13 | S 18 | SSW 16 | SSW 16 | SSW 15 | SSW 15 | SSW 15 | SSW 14 | SSW 13 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 |
74 | 110 | 156 | 102 | 137 | 98 | 156 | 263 | 259 | 234 | 231 | 167 | 210 | 299 | 515 | 741 | 1029 | 1004 | 784 | 743 | |
Swell 2 Height (m) Direction Period (s) | SW 20 | SSW 19 | SSW 18 | SW 18 | SW 17 | SSW 16 | SSW 12 | SE 10 | SSW 12 | SSE 10 | SSE 9 | SSE 9 | SSE 9 | S 20 | SSW 13 | SSW 13 | W 12 | W 12 | SE 9 | SE 10 |
98 | 148 | 127 | 155 | 148 | 104 | 83 | 45 | 79 | 63 | 54 | 54 | 52 | 373 | 277 | 273 | 25 | 11 | 29 | 23 | |
Swell 3 Height (m) Direction Period (s) | SE 7 | SE 7 | NE 11 | S 10 | SE 8 | SSW 18 | SSW 16 | SSW 12 | SSE 10 | SSW 11 | SSW 11 | S 11 | SSW 11 | SE 9 | SE 9 | W 12 | W 9 | SW 19 | W 12 | W 12 |
13 | 12 | 40 | 17 | 14 | 102 | 100 | 56 | 37 | 24 | 23 | 62 | 41 | 36 | 21 | 25 | 2 | 14 | 11 | 10 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 5 | ENE 6 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | E 6 | E 7 | E 6 | ENE 6 | E 7 | ENE 7 | ENE 7 |
84 | 70 | 117 | 167 | 212 | 219 | 218 | 232 | 252 | 204 | 215 | 188 | 192 | 182 | 200 | 213 | 212 | 262 | 285 | 326 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 31 | 16 | 31 | 16 | 16 | 31 | 31 | 16 | 31 | 16 | 16 | 31 | 31 | 16 | 31 | 33 | 16 | 31 | 33 | 31 |
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











