Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 8 Aug 2026:
- Most powerful swell: Sunday 9 Aug, 8PM (local time) - 2.5ft (0.8m), 10s period, NW swell with 136 kJ wave energy.
Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 0.8m 10s and forecast to arrive on Sunday (Aug 09) at 8PM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 8PM (Sun 9th Aug) | 2.5ft (0.8m) 10s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get into it.
We’re looking at a pretty quiet stretch ahead for Guethary’s famous reef. Right now, the first week is a bit of a write-off. From Saturday 8 August right through to the evening of Monday 17 August, it’s flat or just poor. The swell is tiny, mostly under 3ft, with short, weak periods around 5-10 seconds, and the wind is often cross-onshore or onshore. There’s not enough energy to get excited about – the combined energy stays below 100 (weak) for most of that time, barely hitting three digits on a couple of afternoons, but still poor. That’s a solid ten-day gap with nothing worth paddling out for.
Things start to look a bit more promising on Tuesday morning 18 August. The reef at Guethary - Les Alcyons/Avalanche (France) finally sees a little pulse. Swell is 3ft from the NW at 9 seconds, with combined energy hitting 124 (moderate). The wind is glassy, calm, with a slight air, so it’ll be clean. The wave comment says “surfable but very ordinary” – not a standout, but a chance to get wet after the drought.
The real highlight, the one that’s worth marking on the calendar, lands on Thursday morning 20 August. The swell picks up to 4ft from the NW, period 9 seconds, and combined energy jumps to 179 (moderate). The wind is glassy – calm, with a NNE breeze at 0 mph. That’s clean, glassy surf at a reef that needs good conditions. The water is about average for this time of year, so no surprises there. This is the best on offer: a solid, clean, workable wave for the experts who love this spot. It’s not huge, but it’s clean and the reef will line it up.
Then on Saturday morning 22 August, we get another shot. The swell holds at 4ft from the NW, period 9 seconds, combined energy 220 (moderate). The wind is light cross-off from the SSW at 3 mph, giving clean, lined-up waves. The wave comment says “expect good surf conditions” – this is the second best window. Just be aware the afternoon gets blown out with a moderate onshore breeze.
For the rest of the 16-day window, the surf drops back to poor or marginal. The best calls are the Thursday morning 20 August and Saturday morning 22 August – both clean, moderate energy, and the reef doing its thing. It’s a long wait, but there’s a couple of windows worth chasing.
Rusty.
Short Range ForecastHeavy rain (total 26mm), heaviest during Sat night. Warm (max 26°C on Sat afternoon, min 19°C on Fri night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 24°C on Tue afternoon, min 19°C on Mon night). Wind will be generally light. | ||||||||||||||||||
Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | ||||||||||||||
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) | NNW 6 | NNW 5 | NNW 5 | NW 12 | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | NW 8 | WNW 9 | WNW 9 | WNW 9 | WNW 11 |
Wave Graph  | |||||||||||||||||||
 kJ | 32 | 15 | 10 | 23 | 89 | 117 | 90 | 81 | 81 | 79 | 74 | 57 | 55 | 41 | 31 | 28 | 26 | 17 | 51 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | glassy | cross-on | cross-off | cross-on | on | cross-on | cross-on | on | glassy | glassy | on | cross-on | on | on | cross | on | on | cross-on |
High Tide | 00:20AM2.92m | 1:03PM2.97m | 1:51AM2.98m | 2:25PM3.17m | 3:06AM3.18m | 3:31PM3.46m | 4:06AM3.43m | 4:25PM3.77m | 4:56AM3.64m | 5:13PM4.01m | 5:41AM3.78m | 5:57PM4.15m | |||||||
Low Tide | 6:34AM1.05m | 7:20PM0.94m | 7:56AM0.96m | 8:38PM0.72m | 9:04AM0.74m | 9:41PM0.43m | 10:01AM0.47m | 10:34PM0.15m | 10:50AM0.23m | 11:22PM-0.05m | 11:34AM0.07m | 00:05AM-0.14m | |||||||
 | | |  |  | |  | | |  | | | | | | | | | | |
 | — | 7:03 | — | — | 7:03 | — | — | 7:05 | — | — | 7:05 | — | — | 7:07 | — | — | 7:07 | — | — |
 | 9:21 | — | — | 9:20 | — | — | 9:19 | — | — | 9:16 | — | — | 9:15 | — | — | 9:14 | — | — | 9:13 |
mm | — | — | — | 19 | — | — | 7 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 23 | 23 | 26 | 23 | 23 | 23 | 22 | 21 | 23 | 22 | 22 | 24 | 23 | 22 | 24 | 22 | 22 | 24 | 22 |
Feels °C | 24 | 24 | 26 | 22 | 24 | 24 | 23 | 22 | 25 | 24 | 25 | 25 | 25 | 24 | 26 | 23 | 24 | 26 | 23 |
Swell 1 Height (m) Direction Period (s) | NNW 6 | NNW 5 | NNW 5 | NW 5 | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | NW 8 | WNW 9 | WNW 9 | WNW 9 | WNW 11 |
| kJ | 32 | 15 | 10 | 23 | 89 | 117 | 90 | 81 | 81 | 79 | 74 | 57 | 55 | 41 | 31 | 28 | 26 | 17 | 51 |
Swell 2 Height (m) Direction Period (s) | WNW 9 | W 9 | W 9 | NW 12 | W 9 | W 8 | W 8 | W 8 | NW 4 | NW 5 | NW 11 | NNW 4 | WNW 10 | WNW 9 | WNW 10 | NW 8 | NW 3 | NNW 4 | WNW 9 |
| kJ | 8 | 2 | 2 | 22 | 2 | 1 | 5 | 5 | 5 | 7 | 4 | 2 | 9 | 8 | 21 | 20 | 2 | 1 | 16 |
Swell 3 Height (m) Direction Period (s) | — | — | N 10 | W 9 | — | W 6 | — | — | — | — | — | — | W 13 | WNW 12 | — | — | NW 7 | NW 6 | NW 6 |
| kJ | — | — | 2 | 2 | — | 1 | — | — | — | — | — | — | 3 | 14 | — | — | 8 | 2 | 2 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | NW 4 | — | NW 4 | NW 4 | — | — | — | — | — | — | — | — | — | — | WNW 3 |
| kJ | — | — | — | — | 4 | — | 6 | 4 | — | — | — | — | — | — | — | — | — | — | 5 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 864 | 375 | 490 | 1 | 78 | 490 | 54 | 43 | 87 | 1 | 1 | 197 | 43 | 122 | 197 | 31 | 325 | 465 | 17 |
Best forecast wave conditions in La Cote Basque | |||||||||||||||||||
Best forecast wave conditions in France | |||||||||||||||||||
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Information about the Guethary - Les Alcyons/Avalanche Surf forecast
The above surf forecast table for Guethary - Les Alcyons/Avalanche provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Guethary - Les Alcyons/Avalanche can be found by selecting the local surf guide option on the grey menu. Our Guethary - Les Alcyons/Avalanche 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 (Guethary - Les Alcyons/Avalanche) 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 Guethary - Les Alcyons/Avalanche 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.
Guethary - Les Alcyons/Avalanche is 9 km (6 miles) from Biarritz. If you plan a holiday in La Cote Basque, look for hotels and other accommodation in Biarritz. Biarritz has rooms for a wide range of budgets as well as car hire and transport links.
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