Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 24 Aug 2026:
- Best quality surf: Friday 28 Aug, 8AM (local time) - 5.5ft (1.7m), 7s period, WNW swell with cross-offshore winds.
- Most powerful swell: Friday 28 Aug, 8PM (local time) - 8ft (2.5m), 10s period, WNW swell with 1,432 kJ wave energy.
- Next surfable swell (1★+): Friday 28 Aug, 8AM (local time) - 5.5ft (1.7m), 7s 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 Friday (Aug 28) at 8AM. The primary swell is predicted to be 1.7m and 7s period. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 2.5m 10s and forecast to arrive on Friday (Aug 28) at 8PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Tuesday (Aug 25) at 5AM.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Fri 28th Aug) | 5.5ft (1.7m) 7s |
| Best Surf | 8AM (Fri 28th Aug) | 5.5ft (1.7m) 7s |
| Most Powerful | 8PM (Fri 28th Aug) | 8ft (2.5m) 10s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a proper look at what’s coming our way for Guethary - Les Alcyons/Avalanche (France). This is a reef setup that needs a clean west swell, and it’s strictly for the experts. We’ve got a bit of a slow start, so don’t rush to grab your board just yet.
Right now and for the next few days, it’s pretty grim. Tuesday and Wednesday are a write-off with tiny, weak swell – the combined energy is only around 19 to 60 (weak), and the wind is all wrong. Thursday morning turns glassy, but the swell is still pathetic at 1ft from the northwest, so it’s not worth a paddle. Friday morning sees a bump to 6ft from the WNW, but it’s a cross-onshore breeze with moderate energy (384), and the conditions are only marginal. Friday afternoon gets bigger at 8ft, but the onshore wind is howling at 12 mph, making it a lumpy mess. That’s a pass from me.
Now, Saturday 29th August morning is where we start to get interested. The wind goes glassy from the east, and we’ve got a clean 5ft swell from the northwest with period around 9 seconds. The combined energy is a solid 323 (moderate), and conditions are described as good. That’s a nice little session for the early crew. Sunday 30th August morning is very similar – glassy again, 5ft from the NW, energy at 288 – another solid morning window. But both afternoons get chopped up by a north-northwest wind, so get it while it’s clean.
There’s a bit of a lull through Monday and Tuesday (1st September) with bumpy, onshore winds and messy surf. The morning of Tuesday 1st has 6ft from the WNW and energy up to 501 (moderate), but the cross-onshore wind keeps it from being great. Wednesday 2nd September morning is glassy but tiny at 3ft, so only worth it if you’re desperate.
The real standout, the one to circle on your calendar, is Sunday 6th September. The morning brings a solid 6ft from the northwest with a longer 11-second period – proper groundswell energy. The combined energy is a massive 924 (strong), and the wind is glassy from the south-southeast. Conditions are set to be very good. This is the pick of the forecast. The afternoon holds up at 6ft but the wind goes cross-shore from the northeast, so the morning is the window to aim for.
We then get a couple of messy, windy days, but hold on – Tuesday 8th September morning is a big one. The swell jumps to 10ft from the WNW with a very long 15-second period. The combined energy rockets to 4314 (very strong). That’s serious groundswell, only for experts, and it will be a bit choppy with a moderate cross-onshore. The afternoon stays at 10ft with a period of 14 seconds, and the wind eases to onshore. This is raw power – reef breaks will handle it well, but beach breaks will be straight and angry. Finally, Wednesday 9th September morning looks like a great recovery: 5ft from the NW, 11-second period, glassy wind from the WSW, and very good conditions. That’s a clean, juicy morning to wrap things up.
So overall, the week starts flat and poor. The best windows are the mornings of Saturday 29th and Sunday 30th August for smaller, clean waves, and the absolute standouts are the mornings of Sunday 6th and Wednesday 9th September for quality, powerful surf. The big 10ft day on the 8th is for experts only. The water temp is about average for the time of year, so no surprises there.
Stay stoked, and I’ll see you out there.
Rusty
Short Range ForecastSome drizzle, heaviest during Thu morning. Warm (max 35°C on Wed afternoon, min 19°C on Tue night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 3mm), mostly falling on Thu night. Warm (max 25°C on Sat afternoon, min 17°C on Fri morning). Wind will be generally light. | ||||||||||||||||||
Tuesday 25 | Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | ||||||||||||||
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 6 | W 4 | NW 12 | NW 11 | NW 10 | WNW 10 | WNW 9 | NW 8 | WNW 8 | WNW 5 | WNW 8 | WNW 10 | WNW 10 | NW 9 | NW 9 | NW 8 | NW 8 | WNW 8 | WNW 7 |
Wave Graph | |||||||||||||||||||
2 | 9 | 23 | 31 | 26 | 37 | 31 | 17 | 126 | 73 | 384 | 1147 | 766 | 323 | 275 | 244 | 288 | 166 | 70 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-on | on | cross-off | off | cross-off | cross-off | glassy | on | cross | cross-on | on | cross-on | glassy | cross-on | glassy | glassy | cross-on | cross-on |
High Tide | 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 | 6:31AM3.68m | 6:45PM3.89m | |||||||
Low Tide | 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 | 12:31PM0.16m | 00:54AM0.10m | ||||||
— | 7:20 | — | — | 7:22 | — | — | 7:24 | — | — | 7:24 | — | — | 7:26 | — | — | 7:26 | — | — | |
8:55 | — | 8:53 | — | — | 8:52 | — | — | 8:51 | — | — | 8:49 | — | — | 8:47 | — | — | 8:45 | — | |
mm | — | — | — | — | — | — | — | 1 | — | 3 | — | — | — | — | — | — | — | — | — |
Temp °C | 25 | 23 | 24 | 22 | 23 | 35 | 26 | 20 | 25 | 22 | 20 | 21 | 21 | 21 | 25 | 21 | 20 | 23 | 21 |
Feels °C | 27 | 22 | 24 | 24 | 24 | 33 | 27 | 21 | 24 | 18 | 19 | 18 | 19 | 21 | 24 | 22 | 21 | 23 | 21 |
Swell 1 Height (m) Direction Period (s) | — | NW 13 | WNW 5 | WNW 6 | NW 10 | WNW 6 | WNW 9 | WNW 6 | WNW 8 | NW 11 | WNW 8 | — | WNW 10 | NW 9 | NW 9 | NW 8 | NW 8 | WNW 8 | WNW 7 |
— | 7 | 20 | 21 | 26 | 23 | 31 | 10 | 126 | 5 | 384 | — | 766 | 323 | 275 | 244 | 288 | 166 | 70 | |
Swell 2 Height (m) Direction Period (s) | NW 6 | NW 9 | NW 12 | NW 11 | WNW 5 | WNW 10 | WNW 6 | NW 8 | — | — | — | — | — | — | — | — | — | NNW 8 | NNW 7 |
2 | 3 | 23 | 31 | 11 | 37 | 8 | 17 | — | — | — | — | — | — | — | — | — | 6 | 15 | |
Swell 3 Height (m) Direction Period (s) | — | — | W 8 | — | WNW 7 | — | NNW 3 | — | — | — | — | — | — | — | — | — | — | — | — |
— | — | 1 | — | 10 | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | W 4 | — | — | — | — | — | — | — | WNW 5 | — | WNW 10 | — | — | — | — | — | — | — |
— | 9 | — | — | — | — | — | — | — | 73 | — | 1147 | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 350 | 313 | 197 | 1 | 1 | 1 | 3 | 71 | 35 | 17 | 12 | 436 | 12 | 0 | 87 | 0 | 0 | 87 | 31 |
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.











