Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 26 Aug 2026:
- Best quality surf: Friday 28 Aug, 11PM (local time) - 7ft (2.1m), 10s period, WNW swell with cross-offshore winds.
- Most powerful swell: Saturday 29 Aug, 2AM (local time) - 7ft (2.2m), 10s period, WNW swell with 970 kJ wave energy.
- Next surfable swell (1★+): Thursday 27 Aug, 5PM (local time) - 3ft (0.9m), 8s 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 5PM. The primary swell is predicted to be 0.9m and 8s 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 2.2m 10s and forecast to arrive on Saturday (Aug 29) at 2AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.2m 2s period and expected on Friday (Aug 28) at 2AM.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5PM (Thu 27th Aug) | 3ft (0.9m) 8s |
| Best Surf | 11PM (Fri 28th Aug) | 7ft (2.1m) 10s |
| Most Powerful | 2AM (Sat 29th Aug) | 7ft (2.2m) 10s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Hey, Rusty here. Let’s break down what’s coming for Guethary - Les Alcyons/Avalanche. This is an expert-only reef break that’s wide open to a W swell.
The water’s sitting at an unusual 76°, way warmer than you’d expect for this time of year.
We’ve got a quiet start. Wednesday and Thursday are basically flat with the swell energy down in the 30s, so leave the board at home. Friday the 28th of August sees the swell bump up to about 4ft from the WNW, but it’s cross-on and choppy, not worth the paddle out.
The first real standout hits Saturday morning, the 29th of August. You’ve got a clean 6ft NW swell with a light offshore breeze from the E at 3 mph. The energy is pumping at 481, and it’ll be glassy. Expect a crowd here though – it’s often busy. That’s your top pick.
Monday morning, the 31st of August, is your second best window. Another glassy session with a 6ft NW swell and 470 units of energy. The wind is light from the NNE. Clean waves for the experts.
After that, the quality fades. You’ll get a few more semi-clean mornings, like Tuesday the 1st of September (4ft WNW, glassy) and Wednesday the 9th of September (4ft NW, glassy), but nothing with the same punch. The second week sees the swell drop away and the wind turns ugly. From the 4th of September, there’s a long stretch of flat or poor conditions.
Bottom line: circle Saturday the 29th and Monday the 31st of August. Those are your days. After that, the window closes for a while.
Rusty.
Short Range ForecastMostly dry. Warm (max 34°C on Wed afternoon, min 18°C on Fri night). Winds decreasing (fresh winds from the W on Wed night, calm by Thu afternoon). | Days 4-6 Weather SummarySome drizzle, heaviest during Mon night. Warm (max 26°C on Sat afternoon, min 17°C on Sat morning). Wind will be generally light. | ||||||||||||||||||||
Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | |||||||||||||||
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 10 | NW 10 | WNW 9 | WNW 8 | WNW 8 | WNW 8 | WNW 8 | WNW 8 | WNW 10 | NW 9 | NW 8 | NW 8 | WNW 9 | NW 11 | NW 10 | NW 9 | NW 9 | NW 9 | WNW 10 | NW 10 | NW 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 26 | 24 | 31 | 80 | 103 | 71 | 150 | 374 | 970 | 481 | 256 | 211 | 252 | 638 | 400 | 470 | 589 | 437 | 314 | 269 | 162 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | off | cross-off | glassy | glassy | cross | cross-on | cross-on | cross-off | cross-off | cross-on | glassy | cross-on | on | cross | glassy | cross-on | glassy | glassy | cross-on | glassy |
High Tide | 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 | 7:04AM3.68m | 7:19PM3.81m | 7:38AM3.61m | 7:56PM3.66m | ||||||||
Low Tide | 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 | 1:06PM0.19m | 1:28AM0.19m | 1:43PM0.29m | 2:06AM0.36m | |||||||
 |  |  | | |  |  | |  | | | | | | | | |  |  | | | |
 | 7:22 | — | — | 7:24 | — | — | 7:24 | — | — | 7:26 | — | — | 7:26 | — | — | 7:28 | — | — | 7:28 | — | — |
 | — | 8:52 | — | — | 8:51 | — | — | 8:49 | — | — | 8:47 | — | — | 8:45 | — | — | 8:44 | — | — | 8:42 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 1 | — | — |
Temp °C | 24 | 34 | 25 | 21 | 24 | 27 | 21 | 22 | 21 | 21 | 26 | 21 | 20 | 22 | 21 | 20 | 21 | 21 | 18 | 21 | 20 |
Feels °C | 25 | 32 | 20 | 22 | 25 | 23 | 19 | 19 | 20 | 19 | 23 | 21 | 21 | 22 | 22 | 22 | 22 | 20 | 19 | 20 | 20 |
Swell 1 Height (m) Direction Period (s) | NW 10 | NW 10 | WNW 9 | WNW 8 | WNW 8 | WNW 8 | WNW 8 | WNW 8 | WNW 10 | NW 9 | NW 8 | NW 8 | WNW 9 | NW 11 | NW 10 | NW 9 | NW 9 | NW 9 | WNW 10 | NW 10 | NW 9 |
| kJ | 26 | 24 | 31 | 80 | 103 | 71 | 150 | 374 | 970 | 481 | 256 | 211 | 252 | 638 | 400 | 470 | 589 | 437 | 314 | 269 | 162 |
Swell 2 Height (m) Direction Period (s) | NW 5 | WNW 5 | NW 4 | — | — | NW 11 | NW 10 | — | — | — | — | — | — | — | — | — | — | — | NW 9 | — | — |
| kJ | 7 | 5 | 3 | — | — | 5 | 36 | — | — | — | — | — | — | — | — | — | — | — | 50 | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | WNW 5 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | 5 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | SSW 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 21 | 21 | 21 | 1 | 0 | 17 | 12 | 87 | 0 | 0 | 87 | 0 | 12 | 87 | 6 | 0 | 87 | 0 | 0 | 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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