Surf Forecasts:
Ammonias surf forecast from 17 Jul 2026:
- Best quality surf: Tuesday 21 Jul, 2AM (local time) - 2ft (0.6m), 15s period, S swell with cross-offshore winds.
- Most powerful swell: Thursday 23 Jul, 8PM (local time) - 3ft (0.9m), 19s period, SSW swell with 657 kJ wave energy.
- Next surfable swell (1★+): Tuesday 21 Jul, 2AM (local time) - 2ft (0.6m), 15s period with S 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 Tuesday (Jul 21) at 2AM. The primary swell is predicted to be 0.6m and 15s period with a secondary swell of 0.6m and 12s. Another secondary swell of 1.1m and 7s is also forecast. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Ammonias in the next 16 days are 0.9m 19s and forecast to arrive on Thursday (Jul 23) at 8PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 14s period and expected on Thursday (Jul 16) at 11PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 2AM (Tue 21st Jul) | 2ft (0.6m) 15s |
| Best Surf | 2AM (Tue 21st Jul) | 2ft (0.6m) 15s |
| Most Powerful | 8PM (Thu 23rd Jul) | 3ft (0.9m) 19s |
Table - best surf conditions forecast for Ammonias over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s break down what’s coming.
First off, you’re looking at a real dry spell. From Thursday the 16th all the way through Tuesday the 22nd of July, there’s basically nothing worth mentioning. The wind is stuck out of the ENE, mostly cross-on or cross, and it’s chopping up what little swell there is. We’re talking small, weak waves from 2ft to 5ft, but it’s all messy. Don’t bother.
Things start to turn the corner around Wednesday the 23rd of July, but it’s still marginal. The swell builds, but the wind is still a problem. The real window, the only one that’s got me excited, is later in the forecast.
The one spot to focus on is Ammonias (a reef break). It’s not perfect, but it’s the best we’ve got. The pick of the whole 16 days is Tuesday the 28th and Wednesday the 29th of July. We’re looking at a solid 6ft to 7ft swell from the east, with a nice long period around 14 seconds. That’s real groundswell, and for a reef, that long period is a good thing – it’ll wrap in and give you some nice lines. The wind finally drops to a gentle breeze, staying cross-shore. The water temp is about 80°, which is normal for the season. The combined energy is strong, around 1669 to 1797, so there’s plenty of power. Keep in mind, crowds are often a problem here, so get there early.
Before that, on the 26th and 27th, the swell gets bigger – up to 8ft – but it’s a short-period windswell with fresh cross-shore winds. That’s a lot of power (2283 on the 26th), but it’s going to be lumpy and rough. At 8ft, that’s only for experts.
So, if you’re holding out, mark down Tuesday the 28th of July at Ammonias. It’s the best we’re going to see after this long quiet stretch.
Rusty.
Short Range ForecastMostly dry. Warm (max 26°C on Thu afternoon, min 24°C on Thu night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 3mm), mostly falling on Tue morning. Warm (max 26°C on Sun afternoon, min 23°C on Sun night). Wind will be generally light. | |||||||||||||||||||
Thu 16 | Friday 17 | Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | Wednesday 22 | ||||||||||||||
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 17 | SSW 14 | ENE 7 | ENE 7 | ENE 7 | SSW 14 | SSW 14 | ENE 8 | ENE 8 | ENE 8 | S 18 | ENE 8 | S 16 | S 15 | S 15 | S 14 | S 13 | SSW 24 | SSW 23 | SSW 22 |
Wave Graph  | ||||||||||||||||||||
 kJ | 197 | 181 | 158 | 196 | 187 | 207 | 210 | 276 | 264 | 221 | 167 | 199 | 188 | 165 | 343 | 316 | 352 | 437 | 426 | 485 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross | cross-on | cross-on | cross-on | cross | cross | cross | cross | cross | cross | cross-off | cross-on | cross | cross | cross-on | cross-on | cross-on |
High Tide | 5:45PM0.67m | 5:57AM0.28m | 6:18PM0.59m | 7:07AM0.31m | 6:48PM0.51m | 8:26AM0.35m | 7:13PM0.43m | 9:50AM0.41m | 7:25PM0.35m | 11:06AM0.46m | 12:06PM0.52m | |||||||||
Low Tide | 00:42AM0.08m | 11:11AM0.05m | 1:14AM0.06m | 12:04PM0.14m | 1:46AM0.05m | 1:11PM0.23m | 2:18AM0.05m | 2:53PM0.29m | 2:52AM0.04m | 3:30AM0.04m | 4:16AM0.04m | |||||||||
 |  |  | | | | | | | |  | | | |  | |  | | | | |
 | — | — | 6:03 | — | — | 6:03 | — | — | 6:03 | — | — | 6:03 | — | — | 6:05 | — | — | 6:05 | — | — |
 | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:21 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | 2 | — | — | 1 |
Temp °C | 26 | 25 | 26 | 26 | 25 | 26 | 26 | 25 | 25 | 26 | 24 | 25 | 26 | 24 | 25 | 26 | 25 | 26 | 26 | 24 |
Feels °C | 26 | 25 | 26 | 26 | 26 | 26 | 26 | 25 | 24 | 26 | 23 | 24 | 26 | 24 | 25 | 25 | 25 | 25 | 26 | 23 |
Swell 1 Height (m) Direction Period (s) | W 14 | SSW 14 | W 14 | SSW 16 | SSW 13 | SSW 14 | SSW 14 | SE 9 | S 12 | S 13 | S 11 | S 12 | S 16 | S 15 | S 15 | S 14 | S 13 | S 13 | S 13 | S 13 |
| kJ | 203 | 180 | 140 | 196 | 187 | 207 | 210 | 46 | 113 | 86 | 65 | 67 | 188 | 165 | 343 | 316 | 352 | 342 | 173 | 212 |
Swell 2 Height (m) Direction Period (s) | SSW 13 | W 14 | SSW 12 | W 14 | W 13 | SE 8 | SE 9 | S 12 | SE 9 | SE 8 | S 18 | S 16 | S 11 | S 12 | SW 17 | SW 16 | SSW 26 | SSW 24 | SSW 23 | SSW 22 |
| kJ | 113 | 146 | 56 | 134 | 87 | 28 | 36 | 75 | 49 | 33 | 162 | 137 | 57 | 112 | 73 | 65 | 224 | 437 | 426 | 485 |
Swell 3 Height (m) Direction Period (s) | SSW 17 | SSE 8 | SSW 16 | SSW 12 | SSE 7 | WNW 13 | WNW 13 | WNW 12 | W 12 | SSE 19 | SE 6 | SW 18 | SE 7 | SW 16 | SSW 11 | SE 6 | E 15 | E 13 | S 10 | E 12 |
| kJ | 197 | 22 | 100 | 82 | 21 | 56 | 56 | 29 | 25 | 120 | 10 | 82 | 11 | 69 | 25 | 10 | 38 | 127 | 78 | 113 |
Wind waves Height (m) Direction Period (s) | ENE 7 | ENE 6 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 6 | ENE 8 | ENE 8 | ENE 8 | ENE 6 | ENE 8 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 7 | ENE 6 |
| kJ | 120 | 181 | 158 | 170 | 180 | 171 | 200 | 276 | 264 | 221 | 167 | 199 | 157 | 131 | 158 | 140 | 163 | 163 | 137 | 147 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 31 | 33 | 31 | 31 | 16 | 31 | 31 | 16 | 31 | 16 | 16 | 31 | 31 | 0 | 31 | 31 | 16 | 31 | 38 | 38 |
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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