
Surf Forecasts:
Ammonias surf forecast from 4 Sep 2026:
- Best quality surf: Monday 7 Sep, 5PM (local time) - 21ft (6.5m), 15s period, SSW swell with onshore winds.
- Most powerful swell: Monday 7 Sep, 8PM (local time) - 30ft (9.0m), 14s period, SSW swell with 30,669 kJ wave energy.
- Next surfable swell (1★+): Monday 7 Sep, 5PM (local time) - 21ft (6.5m), 15s period with SSW 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 Monday (Sep 07) at 5PM. The primary swell is predicted to be 6.5m and 15s period with a secondary swell of 5.0m and 9s. The wind is predicted to be onshore as the swell arrives.
The most powerful waves expected at Ammonias in the next 16 days are 9.0m 14s and forecast to arrive on Monday (Sep 07) at 8PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.9m 9s period and expected on Tuesday (Sep 08) at 5AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5PM (Mon 7th Sep) | 21ft (6.5m) 15s |
| Best Surf | 5PM (Mon 7th Sep) | 21ft (6.5m) 15s |
| Most Powerful | 8PM (Mon 7th Sep) | 30ft (9.0m) 14s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright, this is Rusty. Let's have a look at what's on the cards for Ammonias over the next couple of weeks.
First up, the water temp is sitting at a very warm 81°, which is pretty much bang on average for this time of year, so no surprises there.
Honestly, the outlook for the next week is a bit of a frustrating one. The swell energy is building, with some serious numbers showing up, but the wind is just not playing ball. We kick off on Thursday the 3rd with a 4ft SE swell, but it’s got a cross wind at 19 mph, which is going to leave it lumpy and messy. Not worth getting excited about.
Friday morning the 4th, the swell bumps up to 5ft from the SSE, with a solid 13-second period, and the wave energy is already strong at 1395. But again, that cross-shore breeze is ruining it. That pattern holds through Saturday the 5th, where the swell gets up to 7ft from the ENE and the combined energy jumps to 2479, but the wind remains a problem.
Now, pay attention to Monday the 7th. That morning, the swell direction swings to the SSW, and the period hits a very long 15 seconds, with energy skyrocketing to 7420. The morning is still ruined by a strong cross-onshore breeze, but by Monday afternoon, the wind switches to a direct onshore at a near gale-force 34 mph. The swell is predicted to be a massive 21ft. That’s huge, and while the wind and tide might be favorable for the swell size, the report says it’s too big for this break, so that’s one for the big-wave chargers only, and they’d need to be eyeing the channel, not the peak.
After that, things drop off. From Tuesday the 8th onwards, it’s a pretty grim run. The swell sticks around at 5ft to 7ft during the middle of the week, but it’s almost constantly cross-shore or cross-onshore, and the conditions are described as poor or marginal. The wave energy dips significantly, dropping below 1000 by Wednesday the 9th. There are a couple of afternoons like Tuesday the 8th with lighter winds, but the swell is short-period and weak.
The standout, if you can even call it that, might be the Tuesday the 15th and Wednesday the 16th. The swell picks up again to a clean 7ft to 7ft from the ENE, with a moderate 10-second period and good energy levels around 1479 to 1514. The wind is cross-shore, which is the best we’re going to get, but it’s still not clean. The conditions are still described as marginal.
To be brutally honest, this is a tricky 16-day window for Ammonias. There is no period of clean, glassy surf. The wind is a constant enemy. If you are a kiter, these strong, consistent cross-shore and onshore winds with decent swell might be more interesting than for a surfer. The best advice is to watch the wind, and if you see a light or offshore window appear, that’s your shot. Otherwise, the forecasts can change, and since this spot is fairly consistent, it won’t stay this way forever.
Stay tuned, Rusty.
Short Range ForecastLight rain (total 7mm), mostly falling on Thu afternoon. Warm (max 26°C on Thu afternoon, min 24°C on Fri night). Mainly fresh winds. | Days 5-7 Weather SummaryHeavy rain (total 35mm), heaviest during Mon night. Warm (max 28°C on Tue afternoon, min 24°C on Sun night). Winds decreasing (near gales from the SE on Mon night, calm by Tue night). | |||||||||||||||||||
Thu 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | ||||||||||||||
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) | SE 12 | ENE 7 | SSE 13 | SSE 12 | S 12 | S 12 | ENE 13 | ENE 14 | ENE 13 | ENE 12 | SSW 14 | SSW 15 | SSW 15 | SSW 10 | ENE 11 | ENE 10 | SSW 14 | SSW 14 | SSW 13 | ENE 7 |
Wave Graph | ||||||||||||||||||||
486 | 474 | 778 | 715 | 661 | 746 | 1512 | 1665 | 1556 | 1461 | 2530 | 5735 | 18423 | 3976 | 817 | 520 | 356 | 341 | 257 | 222 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross | cross | glassy | cross-on | cross | cross |
High Tide | 10:57AM0.61m | 12:04PM0.65m | 11:37PM0.20m | 12:57PM0.68m | 00:45AM0.25m | 1:42PM0.69m | 1:36AM0.30m | 2:20PM0.68m | 2:21AM0.36m | 2:54PM0.66m | 3:04AM0.41m | |||||||||
Low Tide | 2:01AM0.05m | 3:24AM0.06m | 8:23PM0.17m | 8:30PM0.15m | 6:02AM0.04m | 8:46PM0.13m | 7:02AM0.02m | 9:05PM0.11m | 7:55AM0.03m | 9:25PM0.09m | ||||||||||
— | — | 6:20 | — | — | 6:20 | — | — | 6:20 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | |
6:52 | — | — | 6:51 | — | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | |
mm | 1 | 1 | — | — | — | 1 | — | 3 | 1 | 5 | 7 | 3 | 4 | 14 | 2 | — | — | — | 1 | 1 |
Temp °C | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 24 | 26 | 27 | 26 | 27 | 28 | 26 | 27 | 27 | 26 |
Feels °C | 24 | 24 | 23 | 23 | 23 | 25 | 25 | 24 | 25 | 25 | 25 | 24 | 25 | 20 | 28 | 30 | 30 | 29 | 28 | 27 |
Swell 1 Height (m) Direction Period (s) | SE 12 | SSE 11 | SSE 13 | SSE 12 | S 12 | S 12 | S 12 | S 12 | SSW 13 | SSW 13 | SSW 14 | SSW 15 | SSW 15 | ENE 12 | S 9 | ENE 10 | ENE 9 | ENE 8 | ENE 8 | E 13 |
486 | 329 | 778 | 715 | 661 | 746 | 846 | 989 | 965 | 847 | 2530 | 5735 | 18423 | 1121 | 561 | 520 | 221 | 140 | 122 | 171 | |
Swell 2 Height (m) Direction Period (s) | S 14 | E 12 | E 14 | E 14 | E 14 | E 14 | SSW 18 | N 9 | SSW 16 | SSW 15 | — | SSE 8 | — | SSW 15 | ENE 11 | S 8 | S 8 | SSW 14 | SSW 13 | SSW 13 |
246 | 109 | 196 | 289 | 401 | 472 | 121 | 6 | 362 | 644 | — | 299 | — | 494 | 817 | 309 | 129 | 341 | 257 | 178 | |
Swell 3 Height (m) Direction Period (s) | E 13 | S 13 | SW 12 | WSW 13 | NNE 11 | SSW 18 | NNE 10 | N 11 | SSE 10 | SSE 10 | — | — | — | NW 12 | SSW 15 | SSW 15 | SSW 14 | S 8 | E 13 | S 7 |
80 | 92 | 6 | 16 | 12 | 121 | 18 | 9 | 38 | 38 | — | — | — | 6 | 487 | 456 | 356 | 74 | 176 | 28 | |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 13 | ENE 14 | ENE 13 | ENE 12 | ENE 12 | E 8 | SE 9 | SSW 10 | W 7 | — | — | — | — | ENE 7 |
400 | 474 | 415 | 376 | 348 | 330 | 1512 | 1665 | 1556 | 1461 | 1564 | 1386 | 4231 | 3976 | 72 | — | — | — | — | 222 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 31 | 46 | 31 | 31 | 16 | 31 | 16 | 16 | 31 | 38 | 46 | 231 | 296 | 33 | 32 | 32 | 0 | 12 | 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










