Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 13 Aug 2026:
- Best quality surf: Saturday 15 Aug, 8PM (local time) - 3ft (0.9m), 7s period, NW swell with glassy winds.
- Most powerful swell: Saturday 15 Aug, 2AM (local time) - 3.5ft (1.1m), 9s period, WNW swell with 207 kJ wave energy.
- Next surfable swell (1★+): Saturday 15 Aug, 8PM (local time) - 3ft (0.9m), 7s 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 Saturday (Aug 15) at 8PM. The primary swell is predicted to be 0.9m and 7s period with a secondary swell of 0.7m and 8s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.1m 9s and forecast to arrive on Saturday (Aug 15) at 2AM. 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+) | 8PM (Sat 15th Aug) | 3ft (0.9m) 7s |
| Best Surf | 8PM (Sat 15th Aug) | 3ft (0.9m) 7s |
| Most Powerful | 2AM (Sat 15th Aug) | 3.5ft (1.1m) 9s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s get into it.
First up, we’ve got a 16-day window that starts with a real flat spell. There’s nothing doing for a long stretch. It’s not until the morning of Monday, August 24th that we finally see some life around here. From August 13th all the way through to the 23rd, the swell is tiny, the period is short, and the winds just aren’t cooperating. It’s a solid dead zone for over a week and a half. A few sessions in that stretch are glassy and calm, but with waves barely reaching 2ft to 2ft, it’s barely a splash.
Now, holding out for the end of this run. The real standout lands on Monday, August 24th. Guethary - Les Alcyons/Avalanche (France) finally wakes up with a solid 8ft swell out of the NW, period around 9 seconds, and a nice glassy start to the morning—calm winds, zero breeze. This spot is an expert-level reef break and it’s consistent, which is good because the combined swell energy is a hefty 910 (moderate to strong energy). For a place that’s exposed to the west and loves a west swell, this north-west direction is bang on for its optimum. The water here is 76°F, which is much warmer than usual for this time of year by about 4 degrees – a noticeable warm anomaly. Keep in mind, the afternoon brings a cross-onshore wind that throws some chop on the surface, so the morning session is the window. The swell is over 5ft, so it’s not a beginner’s day, but for experts it’s looking promising. Crowds are often an issue here, so expect company.
Following that, Tuesday, August 25th morning also offers a good session with a 5ft swell from the NW, period 9 seconds, and a clean light cross-offshore breeze from the east. The combined energy is 379 (moderate). Still an expert-only wave given the size and reef setup, but the quality holds.
Outside of those two mornings, the rest of the second week drops off again into poor conditions with small waves and onshore wind.
That’s your call. Keep an eye on that Monday 24th window, and if you can dodge the crowds, the Tuesday morning also has some pull.
Rusty.
Short Range ForecastSome drizzle, heaviest during Sat night. Warm (max 27°C on Thu afternoon, min 20°C on Sat morning). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 24°C on Sun afternoon, min 20°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | |||||||||||||||
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) | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | WNW 8 | NW 8 | NW 8 | NW 8 | NW 7 | NW 7 | NW 7 | NW 7 | NW 6 | NNW 6 | NNW 6 | NNW 5 | NW 5 | NNW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 50 | 32 | 93 | 111 | 74 | 207 | 71 | 62 | 109 | 109 | 123 | 105 | 60 | 77 | 69 | 39 | 21 | 25 | 10 | 6 | 12 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | cross | cross-on | on | cross-on | cross-on | cross-on | glassy | cross-on | on | cross-on | cross-on | on | cross | cross-on | on | glassy | glassy | on | cross |
High Tide | 5:57PM4.15m | 6:23AM3.83m | 6:38PM4.16m | 7:02AM3.79m | 7:18PM4.05m | 7:40AM3.68m | 7:56PM3.82m | 8:17AM3.50m | 8:34PM3.53m | 8:54AM3.28m | 9:13PM3.21m | 9:33AM3.04m | 9:57PM2.89m | ||||||||
Low Tide | 11:34AM0.07m | 00:05AM-0.14m | 12:16PM-0.01m | 00:46AM-0.12m | 12:56PM0.03m | 1:25AM0.01m | 1:36PM0.16m | 2:03AM0.24m | 2:16PM0.38m | 2:41AM0.52m | 2:57PM0.65m | 3:21AM0.82m | 3:43PM0.94m | 4:07AM1.12m | |||||||
 | |  |  | |  |  | |  | | | | | | | | | | | | | |
 | 7:07 | — | — | 7:09 | — | — | 7:09 | — | — | 7:11 | — | — | 7:11 | — | — | 7:13 | — | — | 7:15 | — | — |
 | — | — | 9:13 | — | — | 9:12 | — | — | 9:09 | — | — | 9:08 | — | — | 9:07 | — | — | 9:06 | — | — | 9:04 |
mm | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 25 | 27 | 24 | 23 | 24 | 23 | 22 | 23 | 22 | 22 | 24 | 22 | 21 | 23 | 22 | 22 | 24 | 22 | 22 | 24 | 23 |
Feels °C | 28 | 29 | 26 | 25 | 26 | 24 | 24 | 25 | 25 | 24 | 26 | 23 | 23 | 24 | 23 | 23 | 25 | 23 | 24 | 25 | 25 |
Swell 1 Height (m) Direction Period (s) | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | — | NW 5 | NW 6 | NW 8 | NW 8 | NW 8 | NW 7 | NW 7 | NW 7 | NW 7 | NW 6 | NNW 6 | NNW 6 | NNW 5 | NW 5 | NNW 5 |
| kJ | 50 | 32 | 93 | 111 | 74 | — | 34 | 58 | 109 | 109 | 123 | 105 | 60 | 77 | 69 | 39 | 21 | 25 | 10 | 6 | 12 |
Swell 2 Height (m) Direction Period (s) | NW 7 | WNW 12 | NW 6 | — | N 4 | — | WNW 9 | WNW 8 | — | — | — | — | NW 8 | — | — | WNW 9 | NW 7 | WNW 8 | WNW 8 | N 5 | WNW 8 |
| kJ | 12 | 30 | 2 | — | 1 | — | 71 | 62 | — | — | — | — | 18 | — | — | 8 | 7 | 6 | 6 | 2 | 6 |
Swell 3 Height (m) Direction Period (s) | — | NNW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | WNW 9 | — | — | WNW 8 | NW 10 |
| kJ | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | — | — | 6 | 4 |
Wind waves Height (m) Direction Period (s) | — | — | W 3 | WNW 4 | WNW 4 | WNW 9 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | 5 | 5 | 6 | 207 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 1 | 196 | 13 | 136 | 333 | 12 | 136 | 87 | 0 | 13 | 87 | 39 | 43 | 87 | 17 | 31 | 224 | 56 | 543 | 610 | 433 |
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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