Surf Forecasts:
Waimea Rivermouth surf forecast from 18 Aug 2026:
- Best quality surf: Monday 24 Aug, 2AM (local time) - 7ft (2.2m), 12s period, ESE swell with cross-offshore winds.
- Most powerful swell: Monday 24 Aug, 5AM (local time) - 7.5ft (2.3m), 12s period, ESE swell with 1,449 kJ wave energy.
- Next surfable swell (1★+): Tuesday 18 Aug, 5PM (local time) - 2.5ft (0.8m), 13s period with SSE swell.
Best Forecast Surf Conditions for Waimea Rivermouth this week:
The surf forecast for Waimea Rivermouth over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Aug 18) at 5PM. The primary swell is predicted to be 0.8m and 13s period. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Waimea Rivermouth in the next 16 days are 2.3m 12s and forecast to arrive on Monday (Aug 24) at 5AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.9m 6s period and expected on Saturday (Aug 22) at 5PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5PM (Tue 18th Aug) | 2.5ft (0.8m) 13s |
| Best Surf | 2AM (Mon 24th Aug) | 7ft (2.2m) 12s |
| Most Powerful | 5AM (Mon 24th Aug) | 7.5ft (2.3m) 12s |
Table - best surf conditions forecast for Waimea Rivermouth over the next 16 days.
The Lowdown
Alright, Rusty here. Let's check out the mix at Waimea Rivermouth.
To start, it's pretty flat. For the first four or five days, you're looking at waves around 2 to 3 feet max, nothin' with any real power. The combined swell energy is weak to moderate. It’s a slow, sleepy beginning.
We finally get a pulse of life on Sunday the 23rd. That morning shows a sudden jump to a 5-foot east swell, but with a very short period. The energy is ramping up, but those waves will be a bit crumbly and fat.
The real standout period starts right after. Tuesday the 25th is the big one in the first week, with 6-foot east swell in the morning under clean winds. This is a proper set, but at 6 feet, it's gettin' a bit hefty for the groms.
Now, I’m telling you, the absolute best on offer looks to be the afternoon of Wednesday the 26th of August. We’ve got a 4-foot groundswell from the south-southwest with a 12-second period, and that afternoon the wind goes dead glassy. That’s your window. The wave energy is huge for that size (over 900), meaning long, clean lines with plenty of grunt. That is a session you don't miss.
Later, into the weekend of the 29th and 30th, the swell really cranks up, hitting 6 to 8 feet from the east. The wave energy goes through the roof (over 1000, and even 1400). But the wind starts to chop it up, making it a bit of a washing machine. At that size, with that chop, it’s a good day for the kite crew, not so much for a standard log or shortboard.
Early September still has clean, powerful 5 to 6-foot swell, but for pure quality, that glassy Wednesday afternoon on the 26th of August is your winner. The water is a pleasant 80°F, totally normal for the season.
Rusty, out.
Short Range ForecastMostly dry. Warm (max 27°C on Tue morning, min 24°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 29°C on Sun afternoon, min 25°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | |||||||||||||||
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) | S 13 | SSE 13 | S 13 | S 12 | S 12 | E 8 | SW 18 | SW 17 | SSW 17 | SSW 17 | SSW 16 | SSW 16 | SSW 16 | SSW 16 | E 6 | E 7 | SE 10 | ESE 12 | SE 12 | SE 12 | E 8 |
Wave Graph  | |||||||||||||||||||||
 kJ | 165 | 229 | 158 | 103 | 69 | 130 | 154 | 145 | 184 | 195 | 171 | 226 | 173 | 166 | 200 | 267 | 123 | 1332 | 228 | 336 | 442 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-off | cross-off | cross-off | glassy | cross-off | glassy | glassy | glassy | on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 8:43AM0.42m | 5:44PM0.27m | 10:05AM0.43m | 11:29AM0.45m | 12:34PM0.47m | 11:18PM0.16m | 1:21PM0.50m | 00:48AM0.18m | 1:59PM0.52m | 1:32AM0.20m | 2:31PM0.54m | 2:07AM0.23m | |||||||||
Low Tide | 4:02PM0.29m | 1:38AM0.08m | 2:26AM0.09m | 3:45AM0.10m | 9:51PM0.17m | 5:10AM0.09m | 9:28PM0.16m | 6:14AM0.07m | 9:32PM0.15m | 7:02AM0.04m | 9:42PM0.14m | ||||||||||
 | |  | | | |  | |  | | | | | | | | | | | | | |
 | 6:16 | — | — | 6:16 | — | — | 6:16 | — | — | 6:18 | — | — | 6:18 | — | — | 6:18 | — | — | 6:18 | — | — |
 | — | 7:07 | — | — | 7:06 | — | — | 7:05 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — | — | 7:01 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 27 | 26 | 25 | 26 | 26 | 25 | 27 | 27 | 26 | 28 | 28 | 26 | 27 | 28 | 26 | 28 | 29 | 26 | 27 | 27 | 25 |
Feels °C | 29 | 27 | 27 | 27 | 28 | 28 | 29 | 31 | 30 | 31 | 31 | 30 | 29 | 31 | 28 | 29 | 30 | 27 | 28 | 29 | 26 |
Swell 1 Height (m) Direction Period (s) | S 13 | SSE 13 | S 13 | S 12 | S 12 | S 12 | SW 18 | SW 17 | SSW 17 | SSW 17 | SSW 16 | SSW 16 | WNW 12 | WNW 12 | WNW 11 | NW 11 | SE 10 | SE 13 | SE 12 | SE 12 | SE 12 |
| kJ | 165 | 229 | 158 | 103 | 69 | 69 | 154 | 145 | 184 | 195 | 171 | 226 | 142 | 199 | 154 | 117 | 122 | 269 | 228 | 336 | 314 |
Swell 2 Height (m) Direction Period (s) | NE 6 | NE 6 | NNE 7 | NE 7 | NNE 6 | NNE 6 | NE 6 | NNE 6 | NE 7 | NNE 7 | W 10 | W 10 | SSW 16 | SSW 16 | SSW 16 | SE 10 | NW 11 | NW 11 | NNE 6 | NNE 6 | NE 6 |
| kJ | 18 | 8 | 20 | 22 | 16 | 14 | 21 | 17 | 23 | 31 | 49 | 51 | 173 | 166 | 162 | 74 | 119 | 92 | 23 | 34 | 33 |
Swell 3 Height (m) Direction Period (s) | SSE 5 | WNW 12 | WNW 12 | SW 16 | SE 10 | SW 16 | S 11 | S 11 | W 10 | W 10 | NE 7 | NE 7 | WNW 14 | ESE 8 | SE 8 | SSW 15 | SSW 15 | NNE 6 | NW 11 | SSW 13 | SSW 12 |
| kJ | 9 | 49 | 48 | 67 | 33 | 68 | 39 | 39 | 31 | 51 | 23 | 23 | 71 | 41 | 31 | 150 | 123 | 25 | 92 | 102 | 61 |
Wind waves Height (m) Direction Period (s) | E 5 | E 5 | E 5 | E 7 | E 5 | E 8 | ENE 7 | ENE 7 | — | — | — | ENE 7 | ESE 5 | E 6 | E 6 | E 7 | NE 6 | ESE 12 | ENE 7 | E 6 | E 8 |
| kJ | 93 | 143 | 80 | 94 | 51 | 130 | 86 | 71 | — | — | — | 70 | 3 | 239 | 200 | 267 | 20 | 1332 | 181 | 247 | 442 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 149 | 18 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Best forecast wave conditions in Kaua'i | |||||||||||||||||||||
Best forecast wave conditions in United States | |||||||||||||||||||||
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Information about the Waimea Rivermouth Surf forecast
The above surf forecast table for Waimea Rivermouth provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Waimea Rivermouth can be found by selecting the local surf guide option on the grey menu. Our Waimea Rivermouth 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 (Waimea Rivermouth) 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 Waimea Rivermouth 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 Waimea Rivermouth, camping, hotels and condos and appartments in Kaua'i, consider staying in Nawiliwili which is 32 km (20 miles) away. Alternatively, find information about places to stay and car hire in Lihue - Kauai which is 34 km (21 miles) away
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