
Surf Forecasts:
Ammonias surf forecast from 5 Aug 2026:
- Most powerful swell: Wednesday 12 Aug, 2PM (local time) - 4ft (1.2m), 18s period, S swell with 891 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 1.2m 18s and forecast to arrive on Wednesday (Aug 12) at 2PM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 2PM (Wed 12th Aug) | 4ft (1.2m) 18s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, this is Rusty. Let’s be straight up with you: Ammonias is looking at a pretty grim run over the next two weeks. The first week is a write-off, with persistent cross and cross-onshore winds from the ENE keeping things choppy and messy. The combined swell energy stays mostly in the moderate range, around the 350 to 600 mark, but the wind just won’t let it come together. There’s a big gap of about four to five days at the start where I wouldn’t even bother paddling out.
Things start to look a little more interesting around the 12th of August. We see a long-period S/SW groundswell showing up, with periods of 15 to 18 seconds and the combined energy jumping well into the strong range — over 1000. That’s a proper pulse of energy, but the catch is the wind is still cross or cross-on from the ENE at 12 to 13 mph. That’s going to put a chop on the face and spoil the cleanliness.
The best of a bad bunch looks to be Wednesday afternoon the 12th of August and Thursday afternoon the 13th. Those afternoons have the swell from the S at 4ft to 5ft with a period of 15 to 18 seconds, meaning good power and shape potential, but the cross-shore wind will still leave a bit of texture on the surface. The water’s sitting around 80°, which is about average for the time of year — nothing out of the ordinary there.
If I had to pick one standout, it’s the Wednesday afternoon (12th August). That S swell at 4ft and 18 seconds is coming with serious long-period groundswell energy (combined energy at 1181), which is great for this reef break since reefs love that longer period. Just keep an eye on the moderate cross-shore wind — it won’t be glassy, but it’s the best you’re going to get in this 16-day window.
Later in the window, around the 15th to 17th, the swell bumps up to 7ft to 7ft from the ENE, but that’s short-period windswell (6 to 8 seconds) and the wind stays cross or cross-on at 15 to 19 mph. That’s going to be lumpy, messy, and not worth your time unless you’re on a kite.
Honestly, Ammonias is not delivering this run. The consistent thing here is poor conditions. It’s a tough stretch, but forecasts can change, so don’t write the whole season off yet.
Stay patient,
Rusty
Short Range ForecastSome drizzle, heaviest during Fri night. Warm (max 26°C on Wed morning, min 24°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Sat morning. Warm (max 26°C on Sat morning, min 24°C on Sat night). Wind will be generally light. | ||||||||||||||||||||
Wednesday 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | |||||||||||||||
AM | 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 10 | ENE 10 | ENE 9 | ENE 8 | ENE 8 | SSW 14 | SW 21 | SW 20 | ENE 6 | E 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | SSW 15 | SSW 15 | SSW 15 | SSW 14 | S 20 |
Wave Graph | |||||||||||||||||||||
373 | 312 | 249 | 228 | 217 | 81 | 147 | 98 | 148 | 176 | 226 | 276 | 286 | 294 | 335 | 231 | 237 | 296 | 222 | 207 | 485 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | cross | cross-on | cross | cross | cross-on | cross | cross | cross-on | cross | cross-on | cross | cross | cross | cross-on | cross | cross | cross | cross | cross-on |
High Tide | 10:10AM0.50m | 11:24AM0.57m | 12:26PM0.64m | 1:18PM0.69m | 00:17AM0.19m | 2:05PM0.73m | 1:24AM0.22m | 2:47PM0.75m | 2:17AM0.26m | 3:26PM0.74m | 3:06AM0.30m | ||||||||||
Low Tide | 2:46AM0.02m | 3:47AM0.01m | 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 | |||||||||||
6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | |
— | 7:15 | — | — | 7:14 | — | — | 7:13 | — | — | 7:13 | — | — | 7:12 | — | — | 7:10 | — | — | 7:10 | — | |
mm | — | — | — | — | — | — | — | — | 1 | 1 | — | — | 1 | — | — | — | — | — | — | — | 1 |
Temp °C | 26 | 26 | 25 | 25 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 |
Feels °C | 27 | 27 | 26 | 26 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 27 | 27 | 25 | 26 | 26 | 26 | 27 | 27 | 26 |
Swell 1 Height (m) Direction Period (s) | SSW 11 | SSW 15 | SSW 15 | SSW 14 | SSW 14 | SSW 14 | SSE 7 | 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 |
46 | 87 | 87 | 81 | 80 | 81 | 21 | 74 | 110 | 113 | 102 | 137 | 98 | 156 | 263 | 196 | 237 | 296 | 222 | 207 | 299 | |
Swell 2 Height (m) Direction Period (s) | SSE 13 | SSW 11 | S 12 | SSE 11 | SSE 11 | SSE 7 | SSW 14 | SW 20 | SSW 19 | SSW 18 | SSW 18 | SW 17 | SSW 16 | SSW 12 | SSW 12 | SE 9 | SSE 8 | SE 8 | SSE 9 | SSE 9 | S 20 |
55 | 38 | 46 | 43 | 42 | 21 | 78 | 98 | 148 | 127 | 123 | 148 | 104 | 83 | 56 | 90 | 45 | 60 | 53 | 54 | 485 | |
Swell 3 Height (m) Direction Period (s) | SW 15 | SSE 12 | SSW 11 | SSW 10 | SE 8 | S 11 | SW 21 | SE 7 | SE 8 | NE 11 | SE 8 | SE 8 | SSW 18 | SSW 16 | SSE 10 | SSW 12 | SSW 11 | W 10 | S 11 | SSW 11 | SSE 9 |
60 | 49 | 37 | 19 | 10 | 38 | 115 | 13 | 14 | 29 | 34 | 21 | 102 | 100 | 36 | 83 | 43 | 8 | 62 | 41 | 52 | |
Wind waves Height (m) Direction Period (s) | ENE 10 | ENE 10 | ENE 9 | ENE 8 | ENE 8 | ENE 5 | ENE 7 | ENE 5 | ENE 6 | E 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 |
373 | 312 | 249 | 228 | 217 | 74 | 147 | 77 | 102 | 176 | 226 | 276 | 286 | 294 | 335 | 231 | 193 | 168 | 173 | 135 | 114 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 16 | 16 | 31 | 31 | 16 | 31 | 16 | 16 | 33 | 31 | 16 | 31 | 16 | 16 | 31 | 31 | 16 | 31 | 16 | 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











