
Surf Forecasts:
Ammonias surf forecast from 8 Aug 2026:
- Most powerful swell: Saturday 15 Aug, 8AM (local time) - 11ft (3.5m), 9s period, ENE swell with 1,980 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 3.5m 9s and forecast to arrive on Saturday (Aug 15) at 8AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 12s period and expected on Thursday (Aug 13) at 2AM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 8AM (Sat 15th Aug) | 11ft (3.5m) 9s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's talk about what we've got cookin' at Ammonias.
Right off the bat, the next week and a half is lookin' pretty average for this reef setup. The swell comin' in is pretty mixed and the wind is never truly clean, mostly hangin' in that cross to cross-on range, which keeps things lumpy and a bit frustrating. The water temp is sittin' around 80° which is pretty much normal for this time of year, so at least you won't be shiverin' while you're waitin'.
Saturday the 8th is a write-off; small, choppy, and messy. Sunday the 9th through to about Tuesday the 13th is all in the "marginal" zone. Nothin' to get excited about. You're lookin' at chest to head high waves (5 ft - 5 ft) but that period is short, around 6-7 seconds, so it's weak and walled up. The combined energy is moderate, just a few hundred to start but climbin'. Wednesday the 12th afternoon sees a shift. The swell direction swings to the S and the period jumps to 18 seconds – that's proper groundswell, with very long lines. The combined energy jumps to 993, and then to 1185 on Wednesday afternoon – that's gettin' into moderate-strong territory, but the wind is still cross, which spoils the party.
Thursday the 13th keeps that S swell rollin' in at 5 ft and 16 seconds with solid energy (1257 and 1066), but again, that cross wind holds. By Friday the 14th, the wind picks up to 19 mph from the NE and the swell bumps up. The afternoon sees 7 ft of ENE swell, but it's short period (8 sec) and lumpy. The combined energy is high (1167) but it's a mess. Honestly, this period looks more interesting for kite surfin' than a clean paddle session.
Now, here's where it gets wild, but not exactly good. Saturday the 15th, the swell absolutely goes mental. We're talkin' 13 ft risin' to 18 ft. The combined energy hits 3779 then a massive 10215 – that is very, very strong wave energy. The wind is howlin' onshore at 22-25 mph. This is not a day for the average punter. This is expert-only territory, and even then, the conditions will be treacherous. That continues into Sunday the 16th with 20 ft of SE swell (combined energy 7724) and strong onshore winds. The whole weekend of the 15th-16th is hazardous.
Things start to ease back down from Monday the 17th, but the quality stays marginal. The swell drops to 5 ft-6 ft and the period shortens back to 7 seconds, with cross winds persistin'. The energy drops to the 500-600 range. From the 19th, it's all poor surf with light cross-onshore winds and very low energy.
If you had to pick a standout, and I'm reachin' a bit here, the best bet for the more experienced surfer would be Ammonias on the mornin' of Thursday the 13th. The S swell at 5 ft has a very long period of 16 seconds, givin' the waves real shape and drive. The combined energy of 1257 shows it has some punch. The wind is cross off the NE at 16 mph, so it's not glassy, but it's the most lined-up and powerful swell we see before the storm hits. For a reef like this, that longer period can be magic. But don't expect perfection, it's still a bit lumpy.
Beyond that, there's a long stretch of poor conditions from the 15th to the 23rd. Keep your eyes on the charts, things can change, but right now it's a waitin' game.
Rusty.
Short Range ForecastLight rain (total 4mm), mostly falling on Sat morning. Warm (max 26°C on Sat morning, min 24°C on Mon night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 27°C on Tue afternoon, min 24°C on Tue night). Mainly fresh winds. | ||||||||||||||||||||
Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | |||||||||||||||
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) | SSW 14 | SW 18 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | E 7 | ENE 7 | S 20 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 | S 14 | ENE 8 | ENE 8 |
Wave Graph | |||||||||||||||||||||
156 | 161 | 165 | 225 | 188 | 263 | 259 | 237 | 231 | 231 | 210 | 373 | 515 | 741 | 1029 | 1004 | 784 | 743 | 598 | 650 | 987 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | cross | cross | cross | cross | cross | cross | cross | cross | cross-on | cross-on | cross-on | cross | cross | cross | cross | cross | cross | cross | cross |
High Tide | 1:18PM0.69m | 00:17AM0.19m | 2:05PM0.73m | 1:24AM0.22m | 2:47PM0.75m | 2:17AM0.26m | 3:26PM0.74m | 3:06AM0.30m | 4:02PM0.71m | 3:54AM0.34m | 4:34PM0.66m | 4:44AM0.37m | 5:03PM0.59m | ||||||||
Low Tide | 9:20PM0.16m | 6:02AM-0.03m | 9:35PM0.15m | 7:01AM-0.05m | 9:56PM0.13m | 7:54AM-0.06m | 10:20PM0.12m | 8:43AM-0.04m | 10:44PM0.10m | 9:30AM-0.00m | 11:09PM0.08m | 10:17AM0.05m | 11:35PM0.07m | ||||||||
6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | |
— | 7:13 | — | — | 7:12 | — | — | 7:10 | — | — | 7:10 | — | — | 7:09 | — | — | 7:08 | — | — | 7:08 | — | |
mm | 1 | — | — | — | — | — | 2 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | 1 |
Temp °C | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 27 | 25 | 26 | 27 | 25 | 27 | 27 | 25 | 26 | 26 | 25 |
Feels °C | 26 | 26 | 25 | 26 | 26 | 25 | 27 | 26 | 25 | 27 | 27 | 25 | 25 | 25 | 24 | 26 | 25 | 24 | 24 | 24 | 24 |
Swell 1 Height (m) Direction Period (s) | SSW 14 | SSW 13 | SSW 13 | SSW 13 | S 18 | SSW 16 | SSW 16 | SSW 15 | SSW 15 | SSW 15 | SSW 14 | SSW 13 | S 18 | S 18 | S 16 | S 16 | S 15 | S 15 | S 14 | S 14 | S 14 |
156 | 102 | 137 | 98 | 156 | 263 | 259 | 234 | 231 | 222 | 210 | 299 | 515 | 741 | 1029 | 1004 | 784 | 743 | 598 | 496 | 383 | |
Swell 2 Height (m) Direction Period (s) | SSW 18 | SW 18 | SW 17 | SSW 16 | SSW 12 | SSW 12 | SSW 12 | SE 8 | SSE 9 | SE 9 | SSE 9 | S 20 | SSW 13 | SSW 13 | W 12 | W 12 | W 12 | W 12 | SE 12 | SE 12 | ESE 14 |
127 | 155 | 148 | 104 | 83 | 82 | 79 | 34 | 54 | 37 | 53 | 373 | 273 | 273 | 25 | 11 | 11 | 11 | 21 | 21 | 198 | |
Swell 3 Height (m) Direction Period (s) | NE 11 | SE 8 | SE 8 | SSW 18 | SSW 16 | SSE 10 | SSE 10 | SSW 11 | SSW 11 | S 11 | SSW 11 | SE 8 | SE 8 | WNW 12 | W 12 | SW 19 | SSW 19 | SW 18 | W 12 | W 11 | SE 13 |
40 | 17 | 16 | 102 | 100 | 37 | 35 | 24 | 23 | 63 | 41 | 58 | 35 | 28 | 11 | 14 | 35 | 13 | 11 | 22 | 26 | |
Wind waves Height (m) Direction Period (s) | ENE 6 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | E 7 | ENE 7 | ENE 6 | ENE 6 | E 7 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 8 | ENE 8 |
101 | 161 | 165 | 225 | 188 | 227 | 245 | 237 | 215 | 231 | 198 | 155 | 170 | 171 | 212 | 239 | 247 | 381 | 522 | 650 | 987 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 31 | 16 | 16 | 31 | 16 | 16 | 31 | 16 | 16 | 31 | 31 | 16 | 31 | 31 | 16 | 31 | 31 | 31 | 31 | 31 | 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











