Surf Forecasts:
Waimea Rivermouth surf forecast from 5 Aug 2026:
- Best quality surf: Tuesday 11 Aug, 5PM (local time) - 5ft (1.5m), 7s period, E swell with cross-offshore winds.
- Most powerful swell: Wednesday 12 Aug, 5AM (local time) - 2.5ft (0.8m), 19s period, S swell with 480 kJ wave energy.
- Next surfable swell (1★+): Wednesday 5 Aug, 8AM (local time) - 1.5ft (0.4m), 13s period with S 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 Wednesday (Aug 05) at 8AM. The primary swell is predicted to be 0.4m and 13s period with a secondary swell of 0.4m and 11s. 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 0.8m 19s and forecast to arrive on Wednesday (Aug 12) 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 1.6m 6s period and expected on Tuesday (Aug 11) at 8PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Wed 5th Aug) | 1.5ft (0.4m) 13s |
| Best Surf | 5PM (Tue 11th Aug) | 5ft (1.5m) 7s |
| Most Powerful | 5AM (Wed 12th Aug) | 2.5ft (0.8m) 19s |
Table - best surf conditions forecast for Waimea Rivermouth over the next 16 days.
The Lowdown
Imperial Units
Alright, let’s talk in feet and miles per hour. The first few days are a total bust at Waimea Rivermouth. Wednesday the 5th has a tiny 1ft south swell with a thunderstorm risk—just leave your board in the truck. Water temp is a balmy 81°, which is about normal for the season.
The action starts to build on Saturday the 8th. The afternoon brings a 5ft east swell, but it’s a short-period windswell at 6 seconds. The wind goes glassy, and the energy is moderate (288). Sunday the 9th is similar with 5ft east swell, 7 seconds, and light cross-off winds. Energy is climbing to 383-451. Not epic, but it’s a start.
The real winner of the first week is Monday the 10th afternoon. That session has a 5ft east swell, 7-second period, and the wind is glassy. The combined energy is 467—a solid moderate push. That’s the session to aim for early on.
Now, the second week is where the big energy comes. Tuesday the 11th afternoon holds 5ft from the east at 7 seconds, but the energy jumps to 513. Then Wednesday the 12th: a proper south groundswell at 3ft but with a massive 18-second period. That’s a very long period groundswell, and the energy is a strong 884. The Rivermouth will be working.
But the absolute standout is Thursday the 13th morning. A 4ft south swell, 16-second period, and the energy is a very strong 1099. The wind is light cross-off. This is an expert-level session, and it’s the best of the whole 16-day run. The 15th to the 18th keeps a good run of east swell going, 6ft to 7ft, with periods of 7-8 seconds. Energy holds in the 600-800 range. By the 16th and 17th, the swell is over 6ft, which is too big for beginners. The 18th Tuesday afternoon drops back to 6ft with energy at 439.
After that, it’s all downhill. The 19th and 20th are small and weak.
So, the one to mark on your calendar: Thursday the 13th of August, morning. Long period south groundswell, massive energy, and clean conditions. The Monday 10th afternoon is your second-best bet for a glassy, smaller wave.
Rusty out.
Short Range ForecastLight rain (total 3mm), mostly falling on Wed morning. Warm (max 27°C on Wed morning, min 24°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 27°C on Sat morning, min 24°C on Sun night). Wind will be generally light. | ||||||||||||||||||||
Wednesday 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | |||||||||||||||
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 | E 10 | E 9 | SW 14 | SW 14 | SW 14 | SW 14 | SSW 16 | SW 19 | SSW 14 | E 6 | E 7 | E 7 | E 7 | E 7 | E 7 | E 7 | SSW 15 | E 7 | E 7 | S 20 |
Wave Graph  | |||||||||||||||||||||
 kJ | 52 | 279 | 225 | 54 | 52 | 53 | 52 | 137 | 95 | 115 | 187 | 254 | 217 | 236 | 230 | 205 | 242 | 234 | 178 | 251 | 365 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | glassy | cross-off | cross | glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | glassy | cross-off | cross | cross-off | cross-off |
High Tide | 10:03AM0.44m | 11:24AM0.50m | 12:30PM0.55m | 1:25PM0.60m | 00:14AM0.17m | 2:12PM0.64m | 1:28AM0.19m | 2:54PM0.66m | 2:24AM0.23m | 3:33PM0.65m | 3:14AM0.27m | ||||||||||
Low Tide | 2:59AM0.03m | 4:05AM0.02m | 5:16AM-0.00m | 9:29PM0.16m | 6:22AM-0.03m | 9:47PM0.13m | 7:19AM-0.05m | 10:10PM0.12m | 8:11AM-0.06m | 10:35PM0.11m | |||||||||||
 |  |  | | |  | | | | |  | | | | | | | | | | | |
 | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — |
 | — | 7:15 | — | — | 7:15 | — | — | 7:15 | — | — | 7:14 | — | — | 7:13 | — | — | 7:13 | — | — | 7:12 | — |
mm | 1 | — | — | — | 1 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 27 | 27 | 25 | 27 | 26 | 25 | 26 | 26 | 25 | 27 | 27 | 25 | 27 | 27 | 25 | 27 | 26 | 25 | 27 | 27 | 26 |
Feels °C | 29 | 30 | 28 | 30 | 28 | 28 | 28 | 27 | 27 | 29 | 28 | 26 | 29 | 29 | 27 | 29 | 29 | 27 | 29 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | SSW 11 | SSE 12 | SSW 10 | NE 6 | NNW 8 | SW 14 | SE 7 | SSW 16 | SSW 14 | SSW 14 | SE 6 | SSW 13 | SSW 13 | NE 7 | SSW 16 | SSW 16 | SSW 15 | SSW 15 | SSW 15 | SSW 14 | SSW 14 |
| kJ | 39 | 49 | 33 | 8 | 19 | 53 | 16 | 137 | 77 | 115 | 20 | 99 | 98 | 26 | 198 | 198 | 176 | 234 | 167 | 213 | 243 |
Swell 2 Height (m) Direction Period (s) | S 13 | SSW 11 | SW 15 | S 11 | NE 8 | NNW 7 | SW 14 | SE 6 | SW 19 | SE 6 | SW 18 | NE 6 | NE 7 | S 18 | NE 6 | NE 7 | SE 9 | SE 9 | SE 9 | SE 9 | S 20 |
| kJ | 52 | 37 | 57 | 39 | 17 | 17 | 52 | 11 | 95 | 14 | 81 | 13 | 21 | 156 | 16 | 21 | 49 | 38 | 39 | 49 | 365 |
Swell 3 Height (m) Direction Period (s) | NNE 5 | SW 15 | NE 5 | SW 14 | SW 14 | S 11 | NE 7 | N 7 | N 7 | NE 6 | NE 6 | SE 8 | SW 16 | SSW 12 | SSW 12 | SE 9 | NE 7 | NE 7 | NE 7 | NE 7 | ESE 7 |
| kJ | 5 | 57 | 7 | 54 | 52 | 38 | 14 | 8 | 8 | 11 | 11 | 22 | 68 | 59 | 48 | 43 | 23 | 23 | 25 | 22 | 44 |
Wind waves Height (m) Direction Period (s) | ENE 5 | E 10 | E 9 | ENE 5 | E 5 | E 6 | E 5 | E 5 | E 6 | E 6 | E 6 | E 7 | E 7 | E 7 | E 7 | E 7 | E 7 | E 7 | E 7 | E 7 | E 7 |
| kJ | 28 | 279 | 225 | 47 | 78 | 72 | 50 | 73 | 78 | 85 | 187 | 254 | 217 | 236 | 230 | 205 | 242 | 127 | 178 | 251 | 159 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 0 | 0 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 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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