Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 23 Aug 2026:
- Best quality surf: Thursday 27 Aug, 8PM (local time) - 4ft (1.2m), 8s period, WNW swell with glassy winds.
- Most powerful swell: Friday 28 Aug, 8PM (local time) - 10ft (3.0m), 11s period, NW swell with 2,120 kJ wave energy.
- Next surfable swell (1★+): Thursday 27 Aug, 11AM (local time) - 3ft (0.9m), 9s period with WNW 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 27) at 11AM. The primary swell is predicted to be 0.9m and 9s period with a secondary swell of 0.6m and 5s. 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 3.0m 11s and forecast to arrive on Friday (Aug 28) at 8PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.5m 4s period and expected on Sunday (Aug 23) at 11PM.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11AM (Thu 27th Aug) | 3ft (0.9m) 9s |
| Best Surf | 8PM (Thu 27th Aug) | 4ft (1.2m) 8s |
| Most Powerful | 8PM (Fri 28th Aug) | 10ft (3.0m) 11s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s have a look at what’s in store for our local slab.
Honestly, the next 16 days are a real mixed bag for Guethary - Les Alcyons/Avalanche. This is an expert reef break that needs a specific west-northwest to northwest swell, and we’re just not getting a proper run of it. The first week is pretty grim. We’ve got a long stretch of basically nothing worthwhile from Sunday the 23rd right through to Wednesday the 27th. The swell is tiny, inconsistent, and the period is all over the place. There’s a little bump on the morning of Thursday the 27th, with a glassy 2.9ft from the WNW (9 seconds), but it’s just not enough to get excited about.
Friday the 28th is where things finally get a bit of a pulse. The morning shows a solid 6.6ft swell from the WNW (10 seconds), and the combined energy is up to 804 (moderate). That’s proper size, but it’s a bit of a beast for an expert spot. The wind is a light cross-shore, which is okay, but the afternoon sees it jump to 8.2ft with a nasty onshore wind, making it a mess. The morning on Saturday the 29th is still big at 6.6ft, but the wind is cross-onshore, so it’s going to be lumpy.
The one standout in this whole window is the morning of Sunday the 30th. We’ve got a 3.9ft swell from the NW (8 seconds), but the real winner is the wind: clear skies and a nice light cross-offshore breeze from the east. That will keep the face clean. The combined energy is 201 (moderate), so there’s enough push. It’s not a monster, but it’s the cleanest, most surfable window we’ll see. Be aware that this spot is a consistent one, but it can get crowded, and with the best conditions of the fortnight, it’s likely to be popular.
The first week of September looks like a return to the same old story. Small, weak swells, and the wind is almost always cross-onshore or onshore. The morning of Wednesday the 2nd is glassy, but the swell is tiny at 2.3ft. The 4th and 5th September have some small pulses, but the wind is never right. The water is a very unusual 77.0°F, which is much warmer than normal for this time of year, so you won’t need a thick suit.
Bottom line: if you’ve got to paddle out, make it for the morning of Sunday the 30th. Everything else is either too small, too windy, or too big with the wrong wind.
Short Range ForecastLight rain (total 3mm), mostly falling on Sun night. Warm (max 32°C on Mon afternoon, min 19°C on Sun morning). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 30°C on Wed afternoon, min 17°C on Fri morning). Wind will be generally light. | ||||||||||||||||||||
Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | |||||||||||||||
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) | NW 7 | NW 7 | N 5 | N 5 | NNW 6 | NW 6 | NW 13 | NW 12 | NW 11 | NW 10 | NW 10 | WNW 9 | WNW 9 | WNW 8 | W 8 | WNW 10 | WNW 11 | WNW 11 | WNW 10 | WNW 9 | NW 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 56 | 26 | 11 | 5 | 6 | 2 | 7 | 23 | 43 | 35 | 23 | 31 | 136 | 234 | 200 | 804 | 1822 | 1527 | 772 | 480 | 396 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross | off | cross-off | cross-on | cross-off | cross | cross-on | glassy | glassy | cross | cross | glassy | cross-on | cross-off | cross | on | cross-on | cross-on | on | off |
High Tide | 2:31PM2.73m | 3:07AM2.71m | 3:24PM2.96m | 3:51AM2.93m | 4:05PM3.21m | 4:26AM3.14m | 4:39PM3.45m | 4:59AM3.34m | 5:10PM3.65m | 5:29AM3.50m | 5:41PM3.80m | 6:00AM3.62m | 6:13PM3.88m | ||||||||
Low Tide | 8:39PM1.22m | 8:57AM1.19m | 9:30PM0.99m | 9:43AM0.95m | 10:11PM0.74m | 10:20AM0.71m | 10:46PM0.50m | 10:54AM0.49m | 11:18PM0.31m | 11:26AM0.32m | 11:50PM0.17m | 11:59AM0.21m | 00:22AM0.10m | ||||||||
 | |  | |  |  | | | | | | |  | | | | |  | | | | |
 | 7:18 | — | — | 7:20 | — | — | 7:20 | — | — | 7:22 | — | — | 7:24 | — | — | 7:24 | — | — | 7:26 | — | — |
 | — | 8:58 | — | — | 8:55 | — | — | 8:53 | — | — | 8:52 | — | — | 8:51 | — | — | 8:49 | — | — | 8:47 | — |
mm | — | — | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 24 | 30 | 27 | 28 | 32 | 26 | 26 | 26 | 22 | 25 | 30 | 26 | 22 | 26 | 22 | 21 | 22 | 21 | 20 | 21 | 20 |
Feels °C | 26 | 29 | 27 | 28 | 30 | 25 | 25 | 25 | 24 | 25 | 29 | 26 | 24 | 23 | 22 | 19 | 19 | 20 | 19 | 20 | 20 |
Swell 1 Height (m) Direction Period (s) | NW 7 | NW 7 | N 5 | N 5 | NW 7 | — | NW 13 | NW 4 | NW 11 | NW 7 | WNW 6 | NW 4 | WNW 9 | WNW 8 | WNW 11 | WNW 10 | WNW 11 | WNW 11 | WNW 10 | WNW 9 | NW 9 |
| kJ | 56 | 26 | 11 | 4 | 2 | — | 7 | 2 | 43 | 23 | 14 | 14 | 136 | 234 | 12 | 804 | 1822 | 1527 | 772 | 480 | 396 |
Swell 2 Height (m) Direction Period (s) | W 8 | W 8 | NW 7 | NNW 7 | — | NW 6 | NW 9 | NW 12 | N 3 | NW 10 | NW 10 | WNW 9 | NW 5 | — | — | — | — | — | — | — | — |
| kJ | 6 | 1 | 8 | 5 | — | 2 | 3 | 23 | 1 | 35 | 23 | 31 | 22 | — | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | W 12 | W 10 | W 9 | W 9 | — | N 6 | W 8 | WNW 4 | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | 3 | 8 | 2 | 2 | — | 1 | 1 | 1 | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | N 5 | — | — | NNW 6 | — | WSW 3 | — | — | — | — | — | — | — | W 8 | — | — | — | — | — | — |
| kJ | — | 4 | — | — | 6 | — | 1 | — | — | — | — | — | — | — | 200 | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 1 | 248 | 47 | 345 | 369 | 313 | 460 | 534 | 1 | 1 | 21 | 31 | 0 | 110 | 0 | 12 | 583 | 12 | 12 | 87 | 0 |
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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