Surf Forecasts:
Ammonias surf forecast from 20 Aug 2026:
- Most powerful swell: Wednesday 26 Aug, 5PM (local time) - 2.5ft (0.8m), 18s period, S swell with 395 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 0.8m 18s and forecast to arrive on Wednesday (Aug 26) at 5PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 7s period and expected on Friday (Aug 21) at 5AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 5PM (Wed 26th Aug) | 2.5ft (0.8m) 18s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, let’s get real about the next couple of weeks. It’s a bit of a rough stretch, I ain’t gonna lie. We’re looking at a long, dry spell of proper surf. The models are showing plenty of ocean movement, but it’s mostly messy, onshore energy and not the clean, groomed lines we want.
The first week is a write-off for anything decent. We’re looking at a solid gap with no quality waves on the cards. There’s a pulse of short-period, wind-blown swell around the 23rd to the 25th, with sizes getting up to 6.2ft, but the wind is gonna be howling from the NE at 18.6 mph, making a complete mess of it. The energy is there, moderate to strong (671), but it’s all chop and no shape. This will be more interesting for the kite crew than for us paddle surfers.
Through the 26th and 27th, the swell drops back down and some longer period energy tries to push in, but the NE wind keeps it onshore and junky. It’s not until the end of the month, around August 31st and into September 1st, that we see a bit of an increase in size again, with swell pushing 7.2ft. The energy is strong (1772), and the period is a bit better at 13 seconds, but it’s still cross-shore winds messing with the surface. It’s frustrating, to be honest.
Ammonias is a reef break that’s fairly consistent, so it’s not like it never breaks, but this forecast is a real test of patience. None of these days are looking like standouts. Even the bigger pulses are marred by wind and poor conditions. It’s not until the very end of the forecast window, into the 3rd and 4th of September, that we see some cleaner potential with the wind dropping to a gentle breeze. There’s a promising swell due from the SSW with a very long period of 20 seconds, and the energy is solid (977). That’s the one bright spot, but it’s a long way out and long-period swells can be tricky at reefs like this if the direction isn’t perfect. For now though, don’t get your hopes up for much. We just gotta wait it out.
Short Range ForecastMostly dry. Warm (max 27°C on Thu afternoon, min 24°C on Wed night). Wind will be generally light. | Days 5-7 Weather SummaryModerate rain (total 16mm), heaviest on Tue afternoon. Warm (max 27°C on Sun afternoon, min 25°C on Sat night). Mainly fresh winds. | ||||||||||||||||||
Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | ||||||||||||||
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 16 | SSW 18 | SSW 17 | SW 16 | SSW 17 | SW 16 | SSW 16 | SW 16 | SW 16 | E 7 | E 7 | ENE 7 | ENE 6 | ENE 7 | E 7 | ENE 7 | E 7 | ENE 7 | ENE 7 |
Wave Graph | |||||||||||||||||||
130 | 207 | 195 | 278 | 255 | 261 | 322 | 261 | 251 | 255 | 345 | 317 | 260 | 232 | 233 | 299 | 262 | 293 | 269 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross | cross | on | on | cross | cross-on | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-on | cross-on | cross-on |
High Tide | 11:20AM0.53m | 12:20PM0.56m | 11:30PM0.20m | 1:07PM0.59m | 00:35AM0.22m | 1:46PM0.62m | 1:16AM0.25m | 2:19PM0.63m | 1:51AM0.28m | 2:48PM0.64m | 2:25AM0.31m | ||||||||
Low Tide | 2:14AM0.09m | 3:21AM0.10m | 9:24PM0.19m | 9:13PM0.18m | 5:45AM0.08m | 9:16PM0.18m | 6:37AM0.05m | 9:23PM0.17m | 7:21AM0.04m | 9:34PM0.16m | |||||||||
— | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:18 | — | — | |
7:05 | — | 7:04 | — | — | 7:02 | — | — | 7:01 | — | — | 7:01 | — | — | 7:00 | — | — | 7:00 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | 4 | 4 | 6 | 14 |
Temp °C | 25 | 26 | 27 | 26 | 27 | 27 | 26 | 27 | 27 | 25 | 26 | 27 | 25 | 26 | 26 | 25 | 26 | 26 | 25 |
Feels °C | 26 | 28 | 29 | 29 | 30 | 30 | 30 | 28 | 28 | 25 | 25 | 26 | 25 | 25 | 25 | 25 | 26 | 27 | 26 |
Swell 1 Height (m) Direction Period (s) | SW 16 | NE 7 | NE 7 | ENE 7 | ENE 7 | SW 16 | SSW 16 | SW 16 | SW 16 | SSW 16 | SSW 15 | SSW 15 | SSW 14 | SE 11 | SE 10 | SSW 12 | SE 9 | SE 9 | SSW 14 |
130 | 52 | 79 | 142 | 55 | 261 | 322 | 261 | 251 | 212 | 196 | 188 | 183 | 114 | 84 | 89 | 97 | 83 | 218 | |
Swell 2 Height (m) Direction Period (s) | S 12 | E 8 | SSW 17 | SW 16 | SSW 17 | ENE 7 | W 10 | W 11 | WNW 11 | WNW 11 | S 13 | SE 10 | SE 12 | SSW 14 | SSW 13 | SE 9 | SSW 16 | SSW 16 | SE 9 |
44 | 60 | 195 | 278 | 255 | 43 | 52 | 93 | 95 | 74 | 130 | 58 | 90 | 163 | 139 | 55 | 201 | 140 | 79 | |
Swell 3 Height (m) Direction Period (s) | SE 9 | SSW 18 | W 10 | WSW 9 | NE 7 | NE 7 | SSE 14 | S 14 | SE 8 | S 14 | WNW 11 | WNW 11 | S 13 | S 14 | SSW 18 | SSW 16 | SSW 12 | SSW 12 | S 18 |
22 | 207 | 50 | 26 | 51 | 37 | 62 | 107 | 17 | 107 | 45 | 47 | 89 | 101 | 61 | 105 | 83 | 85 | 167 | |
Wind waves Height (m) Direction Period (s) | ENE 6 | — | — | — | — | — | ENE 7 | ENE 7 | ENE 6 | E 7 | E 7 | ENE 7 | ENE 6 | ENE 7 | E 7 | ENE 7 | E 7 | ENE 7 | ENE 7 |
117 | — | — | — | — | — | 120 | 117 | 203 | 255 | 345 | 317 | 260 | 232 | 233 | 299 | 262 | 293 | 269 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 16 | 12 | 12 | 10 | 33 | 33 | 10 | 31 | 31 | 31 | 31 | 33 | 31 | 31 | 33 | 38 | 46 | 118 | 33 |
Best forecast wave conditions in Kaua'i | |||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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











