Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 5 Aug 2026:
- Best quality surf: Monday 10 Aug, 11PM (local time) - 3ft (0.9m), 8s period, NW swell with glassy winds.
- Most powerful swell: Tuesday 11 Aug, 5AM (local time) - 3.5ft (1.0m), 11s period, NW swell with 224 kJ wave energy.
- Next surfable swell (1★+): Thursday 6 Aug, 8AM (local time) - 3ft (0.9m), 8s period with NW swell.
Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:
The surf forecast for Guethary - Les Alcyons/Avalanche over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Aug 06) at 8AM. The primary swell is predicted to be 0.9m and 8s period with a secondary swell of 0.2m and 11s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.0m 11s and forecast to arrive on Tuesday (Aug 11) at 5AM. Winds are predicted to be cross-offshore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Thu 6th Aug) | 3ft (0.9m) 8s |
| Best Surf | 11PM (Mon 10th Aug) | 3ft (0.9m) 8s |
| Most Powerful | 5AM (Tue 11th Aug) | 3.5ft (1.0m) 11s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright crew, Rusty here. Let’s break down the next couple of weeks.
Honestly, it’s a rough start. From Wednesday the 5th all the way through to the morning of Monday the 18th, the surf is just no good. We’re looking at a solid two-week stretch of flat, weak, or messy conditions. The waves are too small, the periods are too short, or the wind is blowing it out. Nothing worth getting wet for.
But there is a light at the end of the tunnel. Your one and only real shot comes on the morning of Wednesday the 19th of August. Guethary - Les Alcyons/Avalanche is the spot to be. The swell is a clean 4ft from the NW, with a 9-second period, packing moderate energy (255). The wind is dead glassy – that’s about as good as it gets for a reef. The water is 76°, which is way warmer than usual for this time of year. It’s an expert-only wave, and it’s consistent, but expect it to be crowded. That morning is the real deal.
The morning of Thursday the 20th is still on the cards, with another 4ft NW swell (263 energy), but the wind is a light cross-onshore, making it a bit more of a gamble. The afternoon drops to 4ft.
So, to put it simply: it’s a long wait for a short window. Wednesday the 19th morning is your best bet, and it could be a proper session. The rest is a bust.
Rusty.
Short Range ForecastSome drizzle, heaviest during Wed morning. Warm (max 24°C on Fri afternoon, min 17°C on Fri morning). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 7mm), mostly falling on Sun night. Warm (max 24°C on Sat afternoon, min 18°C on Mon 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) | WNW 8 | NW 8 | NW 9 | NW 8 | NW 8 | NNW 8 | NNW 7 | NNW 6 | NNW 6 | NNW 5 | NNW 5 | WNW 5 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 11 | NW 10 | NW 10 | NNW 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 42 | 67 | 88 | 115 | 109 | 98 | 57 | 34 | 37 | 19 | 9 | 25 | 54 | 61 | 81 | 49 | 91 | 96 | 160 | 110 | 96 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | cross-on | cross | on | glassy | glassy | cross-on | cross | on | on | cross-on | cross-on | on | on | cross-on | on | glassy | cross-off | cross-on | cross |
High Tide | 9:30AM3.18m | 9:53PM3.21m | 10:24AM3.04m | 10:56PM3.03m | 11:36AM2.95m | 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 | |||||||
Low Tide | 3:37PM0.76m | 4:09AM0.80m | 4:37PM0.91m | 5:14AM0.97m | 5:53PM1.00m | 6:34AM1.05m | 7:20PM0.94m | 7:56AM0.96m | 8:38PM0.72m | 9:04AM0.74m | 9:41PM0.43m | 10:01AM0.47m | 10:34PM0.15m | ||||||||
 |  |  | |  |  | | | | | |  | | |  |  | | | | | | |
 | 6:58 | — | — | 7:00 | — | — | 7:01 | — | — | 7:03 | — | — | 7:03 | — | — | 7:05 | — | — | 7:05 | — | — |
 | — | — | 9:23 | — | — | 9:22 | — | — | 9:21 | — | — | 9:20 | — | — | 9:19 | — | — | 9:16 | — | — | 9:15 |
mm | 1 | — | — | — | — | — | — | — | — | — | — | 1 | — | — | 5 | 1 | — | — | — | — | — |
Temp °C | 22 | 22 | 22 | 21 | 21 | 20 | 20 | 24 | 23 | 23 | 24 | 23 | 21 | 23 | 22 | 20 | 21 | 21 | 23 | 28 | 25 |
Feels °C | 24 | 22 | 22 | 21 | 20 | 19 | 21 | 23 | 23 | 23 | 24 | 24 | 22 | 24 | 21 | 22 | 23 | 22 | 24 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | WNW 8 | NW 8 | NW 9 | NW 8 | NW 8 | NNW 8 | NNW 7 | NNW 6 | NNW 6 | NNW 5 | NNW 5 | NW 12 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 8 | NW 10 | NW 10 | NNW 9 |
| kJ | 42 | 67 | 88 | 115 | 109 | 98 | 57 | 34 | 37 | 19 | 9 | 22 | 54 | 61 | 81 | 49 | 91 | 78 | 160 | 110 | 96 |
Swell 2 Height (m) Direction Period (s) | NW 11 | NW 11 | — | WNW 10 | WNW 10 | WNW 10 | WNW 10 | WNW 10 | WNW 9 | W 9 | NW 6 | W 9 | W 9 | W 9 | W 8 | NW 4 | NW 13 | NW 11 | W 11 | NW 10 | WNW 10 |
| kJ | 5 | 5 | — | 11 | 10 | 10 | 9 | 9 | 8 | 2 | 2 | 2 | 2 | 2 | 1 | 3 | 27 | 96 | 2 | 4 | 10 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | W 9 | — | — | — | — | W 8 | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | 2 | — | — | — | — | 1 | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | W 3 | WNW 5 | WNW 4 | WNW 4 | — | — | — | — | — | — | W 4 |
| kJ | — | — | — | — | — | — | — | — | — | — | 1 | 25 | 11 | 6 | — | — | — | — | — | — | 14 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 1 | 197 | 87 | 6 | 87 | 0 | 1 | 541 | 31 | 578 | 558 | 31 | 43 | 87 | 91 | 26 | 87 | 0 | 0 | 87 | 13 |
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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