Surf Forecasts:
Ammonias surf forecast from 16 Aug 2026:
- Most powerful swell: Sunday 16 Aug, 11AM (local time) - 15ft (4.5m), 10s period, E swell with 4,190 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 4.5m 10s and forecast to arrive on Sunday (Aug 16) at 11AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 6s period and expected on Thursday (Aug 20) at 11AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 11AM (Sun 16th Aug) | 15ft (4.5m) 10s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright folks, Rusty here. We’re looking at a tough 16-day stretch for Ammonias. Honestly, there is no real surf to get excited about, and it’s a long wait. The first action worth mentioning doesn’t show up until the very end of the month.
For the first two weeks, it’s pretty much a write-off. We’ve got a mix of big, messy, blown-out swells and tiny, weak leftovers. The wind is constantly on it, mostly cross-onshore, and the wave quality is just poor. You’d be fighting a losing battle. The first recommendation for a proper surf session doesn’t pop up until Saturday, August 30th.
On Saturday morning, August 30th, Ammonias might finally offer something. The swell is coming from the SW at 4 ft, with a period of 11 seconds – a decent, long-period groundswell. The combined wave energy reads 1119 (moderate), so there’s some push to it. The wind is light from the ESE at 6 mph, making for just a light cross-onshore breeze with small wind ripples. It’s still a cross-on wind, and the rating is a marginal 2/5, so it’s not perfect, but it’s the best we’ve seen in weeks. The SSW direction leans toward the optimum SSE, so it should wrap in reasonably well. Since this spot is a reef, that long 11-second period will hold up nicely, giving you some shape. The water temp is 80°, which is about average for this time of year.
The Sunday afternoon looks similar, with 4 ft from the SW and a 12-second period, and even more energy at 1230. The wind is a light 6 mph from the east. It’s still only a marginal, 2-out-of-10 call, but you might catch a few clean-ish runners if you’re picky. That’s your only real window. Everything else before that is a no-go. Patience is key here, or find something else to do on the water.
Rusty.
Short Range ForecastHeavy rain (total 43mm), heaviest during Sun afternoon. Warm (max 26°C on Sat afternoon, min 24°C on Mon night). Winds decreasing (strong winds from the E on Sun morning, light winds from the ENE by Mon night). | Days 5-7 Weather SummaryMostly dry. Warm (max 26°C on Tue afternoon, min 24°C on Tue night). Wind will be generally light. | |||||||||||||||||||
Sat 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | ||||||||||||||
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 9 | E 10 | E 10 | ENE 9 | ENE 8 | ENE 8 | ENE 7 | S 14 | S 13 | S 13 | S 13 | SW 16 | ENE 7 | SW 16 | SSW 18 | SSW 17 | SW 16 | SSW 17 | SW 16 | SSW 16 |
Wave Graph  | ||||||||||||||||||||
 kJ | 1432 | 2932 | 4190 | 1101 | 575 | 385 | 330 | 232 | 165 | 165 | 112 | 129 | 107 | 130 | 207 | 195 | 278 | 255 | 258 | 322 |
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-on | cross-on | cross | cross | cross-on | cross | cross | cross-on | cross-on | cross |
High Tide | 5:29PM0.52m | 6:32AM0.43m | 5:50PM0.44m | 7:34AM0.46m | 6:01PM0.36m | 8:46AM0.48m | 5:31PM0.30m | 10:06AM0.50m | 11:20AM0.53m | 12:20PM0.56m | 11:30PM0.20m | |||||||||
Low Tide | 00:00AM0.06m | 12:01PM0.20m | 00:26AM0.06m | 1:11PM0.26m | 00:55AM0.06m | 3:13PM0.30m | 1:28AM0.08m | 2:14AM0.09m | 3:21AM0.10m | 9:24PM0.19m | ||||||||||
 |  |  | | | |  |  | | | | | | |  | | | | | | |
 | — | — | 6:15 | — | — | 6:15 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — |
 | 7:07 | — | — | 7:07 | — | — | 7:06 | — | — | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — |
mm | 2 | 5 | 13 | 14 | 6 | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 26 | 25 | 26 | 26 | 26 | 26 | 25 | 25 | 26 | 25 | 25 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 |
Feels °C | 24 | 24 | 22 | 27 | 26 | 27 | 27 | 26 | 25 | 26 | 26 | 26 | 27 | 27 | 27 | 27 | 27 | 28 | 28 | 27 |
Swell 1 Height (m) Direction Period (s) | S 13 | S 13 | S 14 | SE 9 | SSE 8 | SSE 7 | SSE 6 | S 14 | S 13 | S 13 | S 13 | S 12 | S 12 | E 8 | SSW 18 | SSW 17 | SW 16 | SSW 17 | ENE 7 | ENE 7 |
| kJ | 219 | 173 | 146 | 989 | 247 | 99 | 66 | 232 | 165 | 165 | 112 | 69 | 69 | 82 | 207 | 195 | 278 | 255 | 59 | 64 |
Swell 2 Height (m) Direction Period (s) | S 16 | S 18 | S 17 | S 16 | S 14 | S 14 | S 13 | SSW 6 | SE 9 | SSE 10 | SSE 10 | SW 16 | SE 9 | SW 16 | E 8 | SSE 10 | E 7 | E 7 | SW 16 | SSW 16 |
| kJ | 46 | 98 | 142 | 181 | 229 | 338 | 155 | 10 | 37 | 64 | 63 | 129 | 41 | 130 | 31 | 36 | 51 | 49 | 258 | 322 |
Swell 3 Height (m) Direction Period (s) | SE 13 | WNW 12 | W 12 | S 13 | S 16 | SE 11 | S 15 | SE 11 | SW 17 | SW 18 | WNW 12 | NNE 7 | SSW 16 | S 12 | SSE 10 | S 11 | SE 9 | NNE 6 | SE 9 | SE 9 |
| kJ | 27 | 29 | 25 | 121 | 127 | 19 | 150 | 30 | 76 | 80 | 28 | 20 | 103 | 71 | 35 | 23 | 41 | 26 | 39 | 36 |
Wind waves Height (m) Direction Period (s) | ENE 9 | E 10 | E 10 | ENE 9 | ENE 8 | ENE 8 | ENE 7 | ENE 7 | ENE 6 | ENE 6 | ENE 6 | ENE 6 | ENE 7 | NE 6 | NE 6 | ENE 7 | NE 6 | — | NNE 6 | — |
| kJ | 1432 | 2932 | 4190 | 1101 | 575 | 385 | 330 | 227 | 153 | 121 | 97 | 83 | 107 | 42 | 80 | 124 | 32 | — | 27 | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 31 | 38 | 231 | 133 | 126 | 126 | 126 | 16 | 31 | 31 | 16 | 31 | 31 | 16 | 31 | 31 | 10 | 31 | 14 | 10 |
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
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