Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 8 Aug 2026:
- Best quality surf: Monday 10 Aug, 2AM (local time) - 2.5ft (0.7m), 10s period, NW swell with glassy winds.
- Most powerful swell: Thursday 13 Aug, 8PM (local time) - 2.5ft (0.8m), 12s period, WNW swell with 161 kJ wave energy.
- Next surfable swell (1★+): Monday 10 Aug, 2AM (local time) - 2.5ft (0.7m), 10s 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 Monday (Aug 10) at 2AM. The primary swell is predicted to be 0.7m and 10s period with a secondary swell of 0.2m and 8s. Another secondary swell of 0.5m and 4s is also forecast. 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 0.8m 12s and forecast to arrive on Thursday (Aug 13) 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+) | 2AM (Mon 10th Aug) | 2.5ft (0.7m) 10s |
| Best Surf | 2AM (Mon 10th Aug) | 2.5ft (0.7m) 10s |
| Most Powerful | 8PM (Thu 13th Aug) | 2.5ft (0.8m) 12s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright, Rusty here, let's look at what's cookin' for the Guethary area.
Honestly, I gotta be straight with you – the next couple of weeks look pretty bleak for the experts-only reef at Guethary - Les Alcyons/Avalanche. We're looking at a proper flat spell to kick things off. The water is sitting at 76° right now, which is way warmer than usual for this time of year, almost 5° above normal, so that's a bit of a weird one.
From the 8th of August all the way through until the 22nd, it's a long, dry stretch of nothing. Tiny waves, cross-shore breezes, and the combined wave energy is mostly weak, barely cracking 100 (14) on the 8th, and only occasionally getting into a moderate range of 120 or so. It's mostly poor conditions, not worth paddling out for.
We finally see a change on the 23rd of August. The swell starts to build, and by Sunday afternoon, we're looking at a solid 8ft of WNW swell on the face. The period jumps to 11 seconds, which gives it some real grunt, and the combined energy rockets up to 1410 – that's a strong pulse of energy. The wind is onshore, but with that much power, this spot will be holding a lot of water. At 8ft, this is strictly for experts only; it's gonna be a heavy, powerful wave. The morning of the 23rd is a bit smaller, around 6ft, but with the same onshore wind. It's not perfect, but it's the only real chance for a wave in the whole outlook.
The 22nd of August morning has a moment of glassy conditions with a small 3ft groundswell, but the energy is weak (96). It's a tease, but it won't have the push to make this reef work.
So, to be honest, the standout is the afternoon of the 23rd of August. It's the only day with any real size and power. Everything else is a write-off. You'll be waiting a long time for that one window.
Keep your eyes on the charts, but for now, it's a waiting game.
Rusty.
Short Range ForecastHeavy rain (total 26mm), heaviest during Sat night. Warm (max 26°C on Sat afternoon, min 19°C on Tue morning). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 27°C on Wed afternoon, min 20°C on Tue night). Wind will be generally light. | |||||||||||||||||||
Sat 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | ||||||||||||||
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) | NNW 5 | NW 12 | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | WNW 10 | WNW 9 | WNW 10 | WNW 12 | WNW 11 | WNW 10 | WNW 10 | WNW 9 |
Wave Graph  | ||||||||||||||||||||
 kJ | 10 | 22 | 89 | 117 | 90 | 81 | 81 | 81 | 76 | 71 | 55 | 44 | 33 | 16 | 32 | 57 | 135 | 111 | 85 | 47 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-off | cross-on | cross-on | glassy | on | on | cross-on | on | on | cross | glassy | cross-on | cross | cross-on | on | cross-on | cross-on | on | cross-on |
High Tide | 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 | 6:23AM3.83m | 6:38PM4.16m | ||||||||
Low Tide | 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 | 12:16PM-0.01m | 00:46AM-0.12m | |||||||
 |  |  | | | | |  | | | | | | | | | | | | | |
 | — | — | 7:03 | — | — | 7:05 | — | — | 7:05 | — | — | 7:07 | — | — | 7:07 | — | — | 7:09 | — | — |
 | — | 9:20 | — | — | 9:19 | — | — | 9:16 | — | — | 9:15 | — | — | 9:14 | — | — | 9:13 | — | — | 9:12 |
mm | — | 24 | — | — | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 26 | 22 | 23 | 23 | 22 | 21 | 23 | 23 | 22 | 25 | 23 | 24 | 27 | 24 | 23 | 25 | 23 | 22 | 23 | 22 |
Feels °C | 26 | 21 | 24 | 24 | 23 | 24 | 24 | 24 | 24 | 26 | 25 | 27 | 28 | 26 | 25 | 27 | 25 | 24 | 24 | 23 |
Swell 1 Height (m) Direction Period (s) | NNW 5 | NNW 4 | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | NW 8 | NNW 4 | WNW 10 | WNW 12 | WNW 11 | WNW 10 | WNW 10 | WNW 9 |
| kJ | 10 | 12 | 89 | 117 | 90 | 81 | 81 | 81 | 76 | 71 | 55 | 44 | 21 | 3 | 32 | 57 | 135 | 111 | 85 | 47 |
Swell 2 Height (m) Direction Period (s) | W 9 | NW 12 | W 9 | W 9 | W 8 | W 7 | NW 4 | NW 5 | NNW 5 | — | WNW 10 | WNW 11 | WNW 10 | WNW 9 | WNW 13 | WNW 10 | NW 6 | NW 4 | NW 5 | NW 6 |
| kJ | 2 | 22 | 2 | 2 | 5 | 4 | 4 | 7 | 2 | — | 9 | 12 | 33 | 16 | 17 | 31 | 2 | 3 | 7 | 15 |
Swell 3 Height (m) Direction Period (s) | N 10 | W 9 | — | — | — | — | — | — | W 11 | — | W 13 | — | — | NW 8 | NW 7 | NW 6 | — | — | — | — |
| kJ | 2 | 2 | — | — | — | — | — | — | 2 | — | 3 | — | — | 9 | 2 | 2 | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | — | NW 4 | W 3 | WNW 4 | NNW 4 | — | — | — | — | — | — | — | WSW 3 | NW 4 | NW 4 | WNW 4 | — | — | W 3 |
| kJ | — | — | 4 | 1 | 8 | 3 | — | — | — | — | — | — | — | 2 | 7 | 5 | 4 | — | — | 6 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 347 | 31 | 54 | 196 | 0 | 26 | 87 | 17 | 4 | 197 | 17 | 1 | 197 | 31 | 189 | 87 | 12 | 43 | 356 | 43 |
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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