Surf Forecasts:
Waimea Rivermouth surf forecast from 6 Sep 2026:
- Best quality surf: Monday 7 Sep, 11PM (local time) - 20ft (6.0m), 14s period, SSW swell with cross-onshore winds.
- Most powerful swell: Monday 7 Sep, 11PM (local time) - 20ft (6.0m), 14s period, SSW swell with 15,112 kJ wave energy.
- Next surfable swell (1★+): Sunday 6 Sep, 8AM (local time) - 6ft (1.9m), 13s period with E 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 Sunday (Sep 06) at 8AM. The primary swell is predicted to be 1.9m and 13s period with a secondary swell of 1.3m and 12s. Another secondary swell of 0.6m and 16s is also forecast. 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 6.0m 14s and forecast to arrive on Monday (Sep 07) at 11PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 2.1m 12s period and expected on Sunday (Sep 06) at 8PM.
| Wave Type | Time (HST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Sun 6th Sep) | 6ft (1.9m) 13s |
| Best Surf | 11PM (Mon 7th Sep) | 20ft (6.0m) 14s |
| Most Powerful | 11PM (Mon 7th Sep) | 20ft (6.0m) 14s |
Table - best surf conditions forecast for Waimea Rivermouth over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s break down what’s coming for Waimea Rivermouth.
We’ve got a decent run ahead, but the first real standout is this Sunday, September 6th. Water temp is about 81°F, right around normal for this time of year.
Sunday morning (September 6th): Waimea Rivermouth sees a 7ft swell from the east with a 13-second period. Cross-off breeze from the east at 9 mph keeps it clean. Combined wave energy is strong at 2123. This is for experienced surfers – size and period give it punch, and the rivermouth handles that long-period energy well. Afternoon stays similar, 7ft from the east, 12-second period, still clean.
Monday (September 7th) gets messy. Morning has rain showers and a fresh easterly breeze at 22 mph, with a 8ft swell shifting to the SSW at 14 seconds. Energy hits 2427, but that wind chops things up. Afternoon brings risk of thunderstorms and strong breeze at 28 mph, 10ft swell, 15-second period, 4711 energy – better for kite surfing than paddling.
Tuesday (September 8th) drops off. Morning has 7ft from the south at 9 seconds, onshore wind from the SSW. Afternoon is tiny, 3ft.
Wednesday (September 9th) morning is small and marginal, but afternoon turns glassy. Only 2ft from the SSW with a 13-second period, light air from the ESE, energy at 230. Small but clean.
From Thursday (September 10th) through Saturday (September 12th) it’s mostly small and ordinary – 1ft to 2ft, some glassy patches.
Now, the standout: Friday, September 18th. Morning and afternoon both have 3ft from the SSW with 17-18 second periods – very long period groundswell, energy at 909, glassy wind. The rivermouth will shape those deep-period waves into clean lines. Saturday, September 19th stays similar with 3ft, 16-second period, glassy morning.
Thursday, September 17th afternoon also shines: 7ft from the east, 8-second period, glassy conditions, energy at 1008 – excellent for experienced surfers, though the east swell isn’t a perfect match for the optimum south direction.
Sunday, September 20th and Monday, September 21st see 5ft to 6ft from the east, 8-second period, cross-off winds, energy in the 500-700 range – solid but short period means less clean.
Best days: Friday, September 18th and Saturday, September 19th – long-period SSW swell with glassy conditions at the rivermouth. Crowds are sometimes here, so expect company.
Rusty.
Short Range ForecastHeavy rain (total 43mm), heaviest during Sun night. Warm (max 27°C on Sun morning, min 24°C on Sun night). Winds decreasing (near gales from the ESE on Mon night, calm by Tue night). | Days 4-6 Weather SummaryLight rain (total 3mm), mostly falling on Thu afternoon. Warm (max 28°C on Wed morning, min 24°C on Thu night). Wind will be generally light. | ||||||||||||||||||||
Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | |||||||||||||||
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) | E 13 | E 12 | SSW 14 | SSW 14 | SSW 15 | SSW 13 | S 9 | SSW 15 | SSW 14 | SSW 14 | SSW 13 | SSW 13 | SSW 13 | SSW 12 | SW 16 | SW 16 | E 7 | E 11 | SW 16 | SW 16 | SW 16 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1355 | 1213 | 1440 | 2234 | 4038 | 9481 | 726 | 376 | 356 | 258 | 187 | 178 | 131 | 121 | 129 | 121 | 110 | 403 | 64 | 64 | 68 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross | cross-off | cross-off | cross-on | on | on | glassy | cross-on | glassy | cross-off | cross | cross | cross-off | cross-off | glassy | cross-off | cross-off | glassy | cross-off |
High Tide | 1:03PM0.59m | 00:49AM0.21m | 1:49PM0.61m | 1:43AM0.26m | 2:28PM0.60m | 2:29AM0.32m | 3:02PM0.58m | 3:12AM0.37m | 3:33PM0.54m | 3:54AM0.42m | 4:02PM0.48m | 4:35AM0.46m | 4:26PM0.43m | ||||||||
Low Tide | 8:41PM0.14m | 6:23AM0.03m | 8:59PM0.12m | 7:21AM0.02m | 9:19PM0.10m | 8:12AM0.02m | 9:39PM0.09m | 9:00AM0.04m | 10:00PM0.07m | 9:47AM0.08m | 10:20PM0.06m | 10:34AM0.12m | 10:41PM0.05m | ||||||||
 |  |  |  |  | |  | |  | | | | | |  | | | | | | | |
 | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:22 | — | — | 6:24 | — | — | 6:24 | — | — | 6:24 | — | — |
 | — | 6:50 | — | — | 6:49 | — | — | 6:47 | — | — | 6:46 | — | — | 6:45 | — | — | 6:45 | — | — | 6:44 | — |
mm | — | — | 11 | 10 | 6 | 13 | 3 | — | — | — | — | — | — | 3 | — | — | — | — | — | — | — |
Temp °C | 27 | 27 | 26 | 25 | 26 | 26 | 27 | 27 | 26 | 28 | 28 | 27 | 27 | 27 | 26 | 26 | 26 | 25 | 26 | 26 | 26 |
Feels °C | 29 | 28 | 27 | 23 | 25 | 20 | 29 | 29 | 30 | 32 | 32 | 32 | 29 | 30 | 29 | 28 | 28 | 26 | 27 | 28 | 27 |
Swell 1 Height (m) Direction Period (s) | S 12 | SSW 12 | SSW 14 | SSW 14 | SSW 15 | NE 8 | S 9 | WNW 10 | WNW 9 | NW 10 | NW 10 | NW 9 | NW 9 | SSW 12 | SW 16 | NNE 7 | NNE 7 | NNE 7 | NNE 7 | NNE 8 | NNE 8 |
| kJ | 488 | 692 | 1440 | 2234 | 4038 | 35 | 726 | 491 | 216 | 251 | 246 | 144 | 79 | 121 | 129 | 30 | 37 | 32 | 37 | 45 | 45 |
Swell 2 Height (m) Direction Period (s) | SSW 16 | NNE 6 | SE 10 | NNW 14 | NW 13 | NW 12 | W 10 | S 8 | S 8 | SSW 14 | SSW 13 | SSW 13 | SSW 13 | NW 8 | NE 7 | SW 16 | SW 15 | SW 15 | SW 16 | SW 16 | SSW 13 |
| kJ | 280 | 34 | 24 | 19 | 44 | 37 | 605 | 317 | 130 | 258 | 187 | 178 | 131 | 44 | 25 | 121 | 110 | 109 | 64 | 64 | 68 |
Swell 3 Height (m) Direction Period (s) | NE 6 | SSW 20 | E 12 | E 12 | E 13 | ENE 12 | SSW 15 | SSW 15 | SSW 14 | S 8 | S 8 | S 8 | SSW 8 | NE 7 | SSW 12 | SSW 12 | SSW 12 | SSW 12 | SE 8 | SW 13 | SW 16 |
| kJ | 29 | 128 | 11 | 12 | 13 | 14 | 408 | 376 | 356 | 82 | 43 | 29 | 19 | 19 | 82 | 46 | 46 | 26 | 18 | 45 | 64 |
Wind waves Height (m) Direction Period (s) | E 13 | E 12 | NE 7 | ESE 7 | SE 9 | SSW 13 | — | — | — | — | — | ENE 8 | ESE 4 | E 5 | E 6 | E 7 | E 7 | E 11 | ENE 11 | ENE 10 | E 10 |
| kJ | 1355 | 1213 | 65 | 181 | 660 | 9481 | — | — | — | — | — | 116 | 3 | 136 | 191 | 111 | 107 | 403 | 343 | 324 | 200 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 0 | 149 | 333 | 261 | 280 | 32 | 32 | 0 | 18 | 0 | 0 | 3 | 3 | 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.
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