Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 10 Aug 2026:
- Most powerful swell: Thursday 13 Aug, 11PM (local time) - 2ft (0.6m), 12s period, WNW swell with 107 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 0.6m 12s and forecast to arrive on Thursday (Aug 13) at 11PM. 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 | 11PM (Thu 13th Aug) | 2ft (0.6m) 12s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get honest about the next couple of weeks. We’re looking at a long dry spell before any real action shows up, so patience is the name of the game.
Right now, there’s nothing doing. The entire first stretch from Tuesday the 11th right through to Saturday the 22nd of August is a write-off. We’re looking at tiny, weak waves across the board – think ankle to knee-high dribble – with onshore winds and choppy, messy conditions. The combined energy is barely registering, with values hanging around 80 to 100 (weak energy). It’s flat, it’s blown out, and there’s no point even paddling out. This is a gap of nearly two weeks with no surf worth chasing.
That all changes on Sunday the 23rd of August. That’s the one to circle on the calendar. The morning session at Guethary - Les Alcyons/Avalanche (reef) is shaping up to be a proper standout. We’ve got a solid 7 ft swell punching in from the NW with a period of 11 seconds, packing some serious energy – the combined energy reading is 1123 (strong to very strong wave energy). This is expert territory, no question. It’s too big for beginners. But for those with the skills, the wind is glassy, absolutely dead calm, and that’s a massive deal. It’ll be clean, lined-up, and powerful. The only downside is the swell direction is W, which is a bit off the optimum, but the size and glassy conditions should more than make up for it. Expect crowds because this spot is consistently good and it’s often busy.
Monday the 24th of August is a step down in size but still has some appeal. The morning shows a 4 ft NW swell, and the wind is cross-offshore from the ENE, keeping things clean. The energy is moderate (447). It’s a good option for a session, but it’s not the standout Sunday is.
By Tuesday morning the 25th, the swell drops to 2 ft with a long 12-second period from the WNW. The wind is glassy again, which is lovely, but the energy is moderate (233). It’ll be clean and pretty, but small. A longboarder’s dream, maybe.
So, the bottom line: the first 12 days are a total bust. The only real, exciting surf is that Sunday the 23rd – a powerful, glassy, expert-only reef break. If you can handle it, that’s the one.
Rusty.
Short Range ForecastMostly dry. Warm (max 28°C on Wed afternoon, min 19°C on Tue morning). Wind will be generally light. | Days 5-7 Weather SummarySome drizzle, heaviest during Sun morning. Warm (max 23°C on Thu night, min 20°C on Thu night). Wind will be generally light. | ||||||||||||||||||
Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | ||||||||||||||
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 9 | NW 9 | NW 9 | NW 8 | NW 8 | WNW 10 | WNW 9 | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | NNW 7 | WNW 9 | NW 8 | NW 8 | NW 7 |
Wave Graph  | |||||||||||||||||||
 kJ | 81 | 76 | 59 | 55 | 44 | 34 | 28 | 50 | 31 | 93 | 77 | 72 | 65 | 45 | 83 | 50 | 78 | 96 | 71 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | glassy | on | cross | glassy | cross-on | cross | on | on | cross | on | on | cross-on | cross-on | on | cross-on | on | on | cross-on |
High Tide | 4:06AM3.43m | 4:25PM3.77m | 4:56AM3.64m | 5:13PM4.01m | 5:41AM3.78m | 5:57PM4.15m | 6:23AM3.83m | 6:38PM4.16m | 7:02AM3.79m | 7:18PM4.05m | 7:40AM3.68m | 7:56PM3.82m | |||||||
Low Tide | 9:41PM0.43m | 10:01AM0.47m | 10:34PM0.15m | 10:50AM0.23m | 11:22PM-0.05m | 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 | ||||||
 | | |  | | | | | | | | |  |  | | |  | |  | |
 | — | 7:05 | — | — | 7:07 | — | — | 7:07 | — | — | 7:09 | — | — | 7:09 | — | — | 7:11 | — | — |
 | 9:16 | — | — | 9:15 | — | — | 9:14 | — | — | 9:13 | — | — | 9:12 | — | — | 9:09 | — | — | 9:08 |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | 4 |
Temp °C | 23 | 22 | 25 | 23 | 24 | 28 | 24 | 24 | 25 | 23 | 22 | 23 | 22 | 21 | 23 | 22 | 21 | 22 | 21 |
Feels °C | 24 | 24 | 26 | 25 | 27 | 29 | 26 | 27 | 27 | 24 | 24 | 24 | 23 | 23 | 24 | 23 | 22 | 22 | 21 |
Swell 1 Height (m) Direction Period (s) | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | WNW 9 | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | NW 6 | NW 6 | NNW 7 | NW 6 | NW 8 | NW 8 | NW 7 |
| kJ | 81 | 76 | 59 | 55 | 44 | 29 | 28 | 50 | 31 | 93 | 77 | 72 | 31 | 33 | 83 | 38 | 78 | 96 | 71 |
Swell 2 Height (m) Direction Period (s) | — | NNW 5 | NNW 4 | WNW 10 | WNW 11 | WNW 10 | NW 8 | NW 7 | WNW 12 | — | — | NW 5 | WNW 9 | WNW 9 | WNW 8 | WNW 9 | — | — | NW 8 |
| kJ | — | 2 | 2 | 9 | 12 | 34 | 9 | 12 | 28 | — | — | 11 | 65 | 45 | 38 | 50 | — | — | 18 |
Swell 3 Height (m) Direction Period (s) | — | W 11 | — | W 13 | — | — | NNW 3 | — | NW 7 | — | — | — | — | — | NW 10 | — | — | — | — |
| kJ | — | 2 | — | 3 | — | — | 1 | — | 8 | — | — | — | — | — | 25 | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | WSW 2 | W 3 | — | WNW 3 | WNW 4 | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | 1 | 1 | — | 4 | 6 | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 1 | 1 | 197 | 17 | 1 | 197 | 31 | 31 | 87 | 17 | 136 | 196 | 43 | 91 | 12 | 43 | 245 | 87 | 136 |
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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