
Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 9 Aug 2026:
- Best quality surf: Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 10s period, NW swell with glassy winds.
- Most powerful swell: Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 10s period, NW swell with 110 kJ wave energy.
- Next surfable swell (1★+): Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 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 11PM. The primary swell is predicted to be 0.8m and 10s period. 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 10s and forecast to arrive on Monday (Aug 10) at 11PM. Winds are predicted to be glassy at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Mon 10th Aug) | 2.5ft (0.8m) 10s |
| Best Surf | 11PM (Mon 10th Aug) | 2.5ft (0.8m) 10s |
| Most Powerful | 11PM (Mon 10th Aug) | 2.5ft (0.8m) 10s |
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 on the cards for the coming weeks.
First thing you need to know - the water is running much warmer than normal for this time of year, sitting at 76°F at Guethary - Les Alcyons/Avalanche. That's a solid 5°F above average, so you can leave the thick spring suit at home.
Now, I'm not gonna sugarcoat it. The next week and a half is basically a write-off. We've got a whole lot of nothing and a whole lot of messy. From the 9th of August right through to the 21st, it's a grim stretch of tiny, weak swell and poor conditions. The swell is barely scraping 3ft, and the energy is threadbare, often well under 100 (119 at its peak, dropping to a measly 16). The wind is a constant problem - mostly cross-on, onshore, or just generally chopping things up. You'll get the odd glassy morning on the 11th, 12th, and 18th, but with the swell so small and the period short (8-10 seconds), it's just not worth the paddle. The wave comment says it all: "poor surf conditions" day after day.
Then, we finally get a flicker of something. On Saturday the 22nd of August, the morning is looking like a bit of a wildcard. The swell is still small at 2ft, but it's got a bit more push with a period of 11 seconds, and the combined energy jumps up to 122 (moderate). The real kicker is the wind: a clean, cross-off breeze from the ENE. That'll put a nice face on the wave. It's "surfable waves but very ordinary conditions" according to the report, but a clean 2ft on a reef break like this can be a lot more fun than the numbers suggest. Just be aware that crowds are often a problem here, so you won't be alone.
Sunday the 23rd of August morning is another one to keep an eye on. Glassy conditions with a 2ft, 9-second NW swell and energy at 118. Again, "surfable but very ordinary", but glassy is glassy.
The one true standout that's worth circling on the calendar is Monday the 24th of August. The morning session is where it's at. The swell is pushing up to 3ft, coming from the NW, and the combined energy hits a solid 228 (moderate). The wind is light and cross-off from the ENE, giving us clean conditions. The report actually says "expect good surf conditions" with a score of 2 out of 10. For a stretch that's been all zeros, that's a big deal. That 9-second period is a decent groundswell, and on a reef like Les Alcyons, it should line up nicely. The afternoon gets ruined by a cross-on breeze, so make it a dawn patrol mission.
So, to sum it up: the first two weeks are a bust. The 22nd and 23rd are worth a look for the clean windows, but the real call is the morning of the 24th of August.
Rusty.
Short Range ForecastLight rain (total 4mm), mostly falling on Sun afternoon. Warm (max 25°C on Tue afternoon, min 19°C on Tue morning). Wind will be generally light. | Days 5-7 Weather SummarySome drizzle, heaviest during Fri night. Warm (max 29°C on Wed afternoon, min 20°C on Thu night). Wind will be generally light. | |||||||||||||||||||
Sun 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | ||||||||||||||
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 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | WNW 10 | WNW 9 | WNW 10 | W 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | NW 5 | WNW 9 |
Wave Graph | ||||||||||||||||||||
117 | 90 | 81 | 81 | 99 | 76 | 59 | 55 | 57 | 34 | 28 | 31 | 48 | 95 | 78 | 74 | 47 | 45 | 40 | 49 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | on | glassy | glassy | on | cross | glassy | cross-on | cross | on | on | cross-on | cross-on | on | cross-on | on | on | cross-on |
High Tide | 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 | 7:02AM3.79m | 7:18PM4.05m | |||||||
Low Tide | 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 | 12:56PM0.03m | 1:25AM0.01m | |||||||
— | — | 7:05 | — | — | 7:05 | — | — | 7:07 | — | — | 7:07 | — | — | 7:09 | — | — | 7:09 | — | — | |
— | 9:19 | — | — | 9:16 | — | — | 9:15 | — | — | 9:14 | — | — | 9:13 | — | — | 9:12 | — | — | 9:09 | |
mm | 1 | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | 5 |
Temp °C | 24 | 22 | 21 | 24 | 23 | 22 | 25 | 23 | 24 | 29 | 26 | 24 | 26 | 23 | 22 | 23 | 22 | 22 | 22 | 21 |
Feels °C | 24 | 23 | 23 | 26 | 25 | 25 | 26 | 25 | 27 | 30 | 29 | 26 | 28 | 24 | 23 | 24 | 22 | 24 | 22 | 23 |
Swell 1 Height (m) Direction Period (s) | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | WNW 9 | WNW 10 | W 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | WNW 8 | NW 6 |
117 | 90 | 81 | 81 | 99 | 76 | 59 | 55 | 57 | 28 | 28 | 31 | 48 | 95 | 78 | 74 | 47 | 45 | 40 | 26 | |
Swell 2 Height (m) Direction Period (s) | W 9 | W 8 | W 7 | — | — | NNW 4 | NNW 4 | WNW 10 | WNW 11 | WNW 10 | NNW 4 | NW 7 | NW 6 | — | — | WNW 4 | — | — | — | WNW 9 |
2 | 5 | 4 | — | — | 2 | 2 | 9 | 12 | 34 | 5 | 2 | 2 | — | — | 7 | — | — | — | 49 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | W 11 | — | W 13 | — | — | NW 8 | — | — | — | — | N 4 | — | — | — | — |
— | — | — | — | — | 2 | — | 3 | — | — | 9 | — | — | — | — | 1 | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | WNW 4 | — | NNW 4 | — | — | — | — | — | — | W 3 | NW 4 | NW 4 | W 4 | WNW 4 | — | WNW 4 | NW 5 | NW 5 | — |
— | 5 | — | 1 | — | — | — | — | — | — | 1 | 7 | 5 | 11 | 10 | — | 26 | 23 | 35 | — | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 147 | 26 | 20 | 87 | 1 | 1 | 197 | 17 | 1 | 197 | 31 | 187 | 196 | 13 | 325 | 796 | 49 | 113 | 196 | 84 |
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.











