
Surf Forecasts:
Ammonias surf forecast from 7 Aug 2026:
- Most powerful swell: Thursday 13 Aug, 2AM (local time) - 4.5ft (1.4m), 16s period, S swell with 1,029 kJ wave energy.
Best Forecast Surf Conditions for Ammonias this week:
The most powerful waves expected at Ammonias in the next 16 days are 1.4m 16s and forecast to arrive on Thursday (Aug 13) at 2AM. 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 11PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 2AM (Thu 13th Aug) | 4.5ft (1.4m) 16s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Well, folks, it’s Rusty here, and I gotta be straight with you—this 16-day stretch for Ammonias is a real tough one to swallow. We’re looking at a long, bleak run with hardly a window worth paddling out for. The first solid recommendation doesn’t show up until mid-period, and even then, it’s nothing to write home about. Let’s break it down.
The overall pattern is dominated by a persistent ENE breeze, mostly cross or cross-onshore, mixing up a lumpy, choppy mess on the reef. The combined swell energy early on is weak to moderate (355 to 600), with short-period windswell (6 to 8 seconds) that just doesn’t have the juice. The water temperature is sitting at 80°F, which is bang on average for this time of year—no surprises there.
From Thursday 6th August right through to Sunday 10th August, it’s a write-off. Scores are zero across the board, with poor surf conditions and a cross-chop that’ll have you fighting the board more than riding it. The swell is tiny or mismatched, and that ENE wind just won’t let up.
Monday 11th August sees a shift in swell direction to SSW, with a longer period of 15 seconds, but the wind is still cross-onshore and the wave height is only 2 ft. The energy jumps to 546 (moderate), but it’s still a marginal call at best. Tuesday 12th August afternoon brings a clearer sky and a more promising S swell with a very long period of 18 seconds and energy climbing to 1198 (strong). The 4 ft swell is small, but those long lines could offer some shape for the reef—if the wind were offshore. It’s not; it’s cross-shore, so expect a bit of texture.
The standout—if you can call it that—is Wednesday 12th August afternoon. The swell is from the south at 4 ft, with a period of 18 seconds (very long, classic groundswell) and combined energy of 1198 (strong). The water is clear, and the wind is cross-shore. For a reef break like Ammonias, that long period is a bonus—it’ll wrap in nicely, with better shape and longer gaps between sets. It’s not big, but it’s the best on offer. However, the cross-shore breeze means it won’t be glassy, so you’ll have to put up with a little cross-chop. Crowds are *often* a thing here, so expect company.
From Thursday 13th August onward, the swell stays from the south with periods of 14 to 16 seconds, but the wind remains cross-shore or cross-onshore, and the scores never climb above a 2 out of 10. The energy is strong (800 to 1198), but the combination of average wave heights and persistent wind keeps it marginal at best. By Saturday 15th August, the swell swings back to short-period ENE windswell, bumping up to 7 ft at 7 seconds, but the wind is fresh cross-shore, creating a lumpy, messy surface. Not worth it.
The tail end of the forecast, from 19th to 21st August, sees the swell drop back to 2 to 2 ft, but with a very long period of 19 to 21 seconds from the SSW/SW. The energy is still moderate to strong (577 to 691), but the wave heights are tiny, and the wind is persistent cross-shore. It’s a tease.
Bottom line: if you’re desperate, Wednesday 12th August afternoon is the pick of a very poor bunch. Don’t expect much else. The first week is a total right-off, and the second week barely offers anything rideable.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Fri night. Warm (max 26°C on Fri morning, min 24°C on Thu night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 5mm), mostly falling on Sun night. Warm (max 27°C on Mon afternoon, min 25°C on Sun night). Wind will be generally light. | ||||||||||||||||||
Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | ||||||||||||||
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 8 | SW 21 | SW 20 | SSW 19 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | SSW 15 | ENE 7 | ENE 7 | S 20 | S 18 | S 18 | S 16 |
Wave Graph | |||||||||||||||||||
135 | 125 | 98 | 148 | 165 | 201 | 261 | 293 | 261 | 293 | 337 | 300 | 231 | 222 | 215 | 373 | 515 | 741 | 1029 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-on | cross | cross | cross | cross | cross-on | cross | cross | cross | cross-on | cross | cross | cross-on | cross | cross-on | cross-on | cross | cross |
High Tide | 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 | 4:02PM0.71m | 3:54AM0.34m | ||||||||
Low Tide | 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 | 8:43AM-0.04m | 10:44PM0.10m | ||||||||
— | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | |
7:14 | — | 7:13 | — | — | 7:13 | — | — | 7:12 | — | — | 7:10 | — | — | 7:10 | — | — | 7:09 | — | |
mm | — | — | — | 1 | — | — | 1 | — | — | 2 | 2 | — | — | 1 | — | — | — | — | — |
Temp °C | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 26 | 27 | 25 | 26 | 27 | 25 | 26 | 26 | 25 |
Feels °C | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 26 | 26 | 25 | 27 | 28 | 26 | 27 | 28 | 26 | 26 | 25 | 25 |
Swell 1 Height (m) Direction Period (s) | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 14 | SSW 13 | SSW 13 | SSW 13 | S 18 | SSW 16 | SSW 16 | SSW 15 | SSW 15 | SE 9 | SSW 14 | SSW 13 | SSW 13 | S 18 | S 16 |
81 | 78 | 74 | 110 | 113 | 102 | 137 | 98 | 156 | 263 | 196 | 179 | 231 | 83 | 207 | 299 | 289 | 741 | 1029 | |
Swell 2 Height (m) Direction Period (s) | S 11 | SE 7 | SW 20 | SSW 19 | SSW 18 | SW 18 | SW 17 | SSW 16 | SSW 12 | SSW 12 | SSW 12 | S 12 | SE 9 | SSW 15 | SSE 9 | S 20 | S 18 | SSW 13 | SE 9 |
38 | 14 | 98 | 148 | 127 | 154 | 148 | 104 | 83 | 56 | 83 | 72 | 62 | 222 | 52 | 373 | 515 | 289 | 22 | |
Swell 3 Height (m) Direction Period (s) | SE 7 | SW 21 | SE 7 | SE 7 | SE 8 | SE 8 | SSE 10 | SSW 18 | SSW 16 | SSE 10 | SSE 10 | SE 8 | SSW 11 | S 11 | SSW 11 | SSE 8 | SE 9 | W 12 | W 12 |
9 | 115 | 12 | 13 | 16 | 18 | 20 | 102 | 100 | 36 | 37 | 35 | 41 | 63 | 40 | 48 | 36 | 25 | 25 | |
Wind waves Height (m) Direction Period (s) | ENE 8 | ENE 7 | ENE 5 | ENE 5 | ENE 6 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 6 | E 6 | ENE 6 |
135 | 125 | 51 | 80 | 165 | 201 | 261 | 293 | 261 | 293 | 337 | 300 | 191 | 215 | 215 | 175 | 160 | 184 | 176 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 31 | 16 | 31 | 31 | 16 | 31 | 16 | 16 | 31 | 16 | 16 | 31 | 31 | 16 | 31 | 16 | 16 | 31 | 31 |
Best forecast wave conditions in Kaua'i | |||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||
Header Global | |||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)
Wind Speed (km/h)
Latest Updates
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











