Surf Forecasts:
Ammonias surf forecast from 4 Sep 2026:
- Best quality surf: Monday 7 Sep, 5PM (local time) - 21ft (6.5m), 16s period, SSW swell with onshore winds.
- Most powerful swell: Monday 7 Sep, 8PM (local time) - 26ft (8.0m), 14s period, SSW swell with 27,868 kJ wave energy.
- Next surfable swell (1★+): Monday 7 Sep, 5PM (local time) - 21ft (6.5m), 16s 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 16s period with a secondary swell of 4.5m 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 8.0m 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 2.0m 10s 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) 16s |
| Best Surf | 5PM (Mon 7th Sep) | 21ft (6.5m) 16s |
| Most Powerful | 8PM (Mon 7th Sep) | 26ft (8.0m) 14s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright everyone, Rusty here. Let’s break down this stretch for Ammonias.
Look, I’m not gonna sugarcoat it—this 16-day run is a bit of a bummer. The first few days are a write-off. Friday the 4th and Saturday the 5th have 5 to 7 feet of swell, but the wind is howling at 19 mph from the ENE, cross-shore, and it’s just tearing the surface apart. The water temp is about average for this time of year, so nothing special. The combined energy is moderate (around 1300-1400), but the waves are lumpy and cross-chop. Not one for the surfboard.
If you’re into kiting, Sunday the 6th might be your jam. The swell jumps to 7 feet, with a very long period of 13 seconds, and the energy is strong (2840-3283). But the wind is cross-onshore and the surface is choppy. Paddle surfers, stay home. Monday the 7th is a beast—over 11 feet of swell, 16-second period, and the energy is massive (up to 21890). That’s too big for this spot, and with a near gale onshore, it’s for experts only, and even then, it’s a wild one.
The second week is a slog. Tuesday the 8th is your best bet, with 6 to 7 feet of ENE swell, an 11-second period, and a cross-shore SSW wind at 12-15 mph. The energy is moderate (1385-2048), and it’s the cleanest we’ll see. After that, it’s small, weak, and messy. From the 9th to the 14th, the swell drops to 3 to 5 feet, the period is short (7-10 seconds), and the wind is stuck on ENE cross or cross-on. The energy is low (under 1000). The 16th and 17th have a very long period (16-18 seconds), but the swell is tiny at 3 feet, so it’s just a lot of water moving with no push.
The one bright spot is Tuesday the 15th. The swell picks up to 7 feet from the ENE, with a 10-second period and moderate energy (1458). The wind is still cross-shore at 19 mph, but it’s the best of the bunch. The break is a reef, which usually likes a longer period, but it’s the only window with some size and a slightly cleaner setup. The crowds are often, so expect company.
Overall, it’s a lean period. The first week is blown out or too big, and the second week is small and choppy. If you’re desperate, hit the morning of the 15th, but don’t expect much. The wait for a proper clean day will be a long one.
Rusty.
Short Range ForecastLight rain (total 8mm), mostly falling on Sun afternoon. Warm (max 26°C on Fri morning, min 24°C on Fri night). Mainly fresh winds. | Days 5-7 Weather SummaryHeavy rain (total 38mm), heaviest during Sun night. Warm (max 28°C on Tue afternoon, min 23°C on Sun night). Winds decreasing (strong winds from the SE on Mon afternoon, calm by Tue night). | ||||||||||||||||||
Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | ||||||||||||||
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 7 | SSE 12 | SSE 12 | S 12 | S 13 | ENE 13 | ENE 13 | ENE 13 | SSW 13 | SSW 14 | SSW 16 | SSW 16 | S 10 | ENE 11 | ENE 11 | SSW 14 | SSW 14 | SSW 13 | ENE 7 |
Wave Graph  | |||||||||||||||||||
 kJ | 456 | 738 | 680 | 736 | 917 | 1474 | 1474 | 1387 | 1877 | 2598 | 6369 | 18739 | 2798 | 934 | 627 | 356 | 341 | 257 | 178 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross | cross | glassy | cross-on | cross-on | cross-on |
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 | — | — | — | — | — | 3 | 1 | 3 | 13 | 3 | 6 | 14 | 1 | — | — | — | 1 | 1 |
Temp °C | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 24 | 26 | 27 | 26 | 27 | 28 | 26 | 27 | 27 | 26 |
Feels °C | 23 | 24 | 24 | 22 | 25 | 24 | 24 | 26 | 26 | 26 | 24 | 25 | 22 | 28 | 30 | 29 | 30 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | SSE 11 | SSE 12 | SSE 12 | S 12 | S 13 | S 12 | S 12 | SSW 12 | SSW 13 | SSW 14 | SSW 16 | SSW 16 | WSW 11 | ENE 11 | ENE 11 | ENE 9 | ENE 8 | ENE 8 | SSW 13 |
| kJ | 329 | 738 | 680 | 736 | 917 | 946 | 1048 | 934 | 1877 | 2598 | 6369 | 18739 | 1348 | 934 | 627 | 266 | 143 | 122 | 178 |
Swell 2 Height (m) Direction Period (s) | E 12 | E 14 | E 14 | E 14 | E 14 | SSW 18 | N 9 | SSW 16 | N 10 | SSE 10 | — | — | ENE 12 | W 8 | S 8 | S 8 | SSW 14 | SSW 13 | E 13 |
| kJ | 109 | 196 | 289 | 485 | 561 | 121 | 13 | 481 | 8 | 36 | — | — | 1252 | 135 | 309 | 161 | 341 | 257 | 171 |
Swell 3 Height (m) Direction Period (s) | S 13 | W 10 | WSW 13 | SSW 20 | SSW 18 | NNE 10 | N 11 | SSE 10 | E 16 | N 9 | — | — | SSW 16 | SSW 15 | SSW 14 | SSW 14 | E 14 | E 14 | S 7 |
| kJ | 92 | 2 | 16 | 37 | 121 | 18 | 9 | 38 | 46 | 7 | — | — | 429 | 487 | 449 | 356 | 257 | 181 | 24 |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 13 | ENE 13 | ENE 13 | ENE 12 | ENE 12 | ENE 8 | SE 9 | S 10 | S 9 | — | — | — | — | ENE 7 |
| kJ | 456 | 415 | 415 | 334 | 306 | 1474 | 1474 | 1387 | 1360 | 1564 | 1114 | 3151 | 2798 | 627 | — | — | — | — | 172 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 46 | 31 | 31 | 31 | 16 | 31 | 16 | 31 | 38 | 118 | 231 | 249 | 32 | 32 | 17 | 0 | 14 | 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
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