Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 21 Sep 2026:
- Best quality surf: Monday 21 Sep, 8AM (local time) - 5.5ft (1.7m), 11s period, NW swell with cross-offshore winds.
- Most powerful swell: Saturday 26 Sep, 8PM (local time) - 6ft (1.9m), 14s period, NW swell with 1,236 kJ wave energy.
- Next surfable swell (1★+): Monday 21 Sep, 8AM (local time) - 5.5ft (1.7m), 11s 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 (Sep 21) at 8AM. The primary swell is predicted to be 1.7m and 11s 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 1.9m 14s and forecast to arrive on Saturday (Sep 26) at 8PM. Winds are predicted to be onshore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Mon 21st Sep) | 5.5ft (1.7m) 11s |
| Best Surf | 8AM (Mon 21st Sep) | 5.5ft (1.7m) 11s |
| Most Powerful | 8PM (Sat 26th Sep) | 6ft (1.9m) 14s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
Short Range ForecastMostly dry. Warm (max 21°C on Mon afternoon, min 16°C on Mon morning). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 26°C on Thu afternoon, min 17°C on Thu morning). Wind will be generally light. | ||||||||||||||||||||
Monday 21 | Tuesday 22 | Wednesday 23 | Thursday 24 | Friday 25 | Saturday 26 | Sunday 27 | |||||||||||||||
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 11 | NW 11 | NW 11 | NW 12 | NW 12 | NW 11 | WNW 16 | WNW 15 | WNW 14 | WNW 13 | WNW 12 | NW 12 | NW 11 | NW 11 | NW 10 | NW 15 | NW 14 | NW 13 | NW 12 | NW 12 | NW 11 |
Wave Graph  | |||||||||||||||||||||
 kJ | 652 | 640 | 488 | 478 | 389 | 237 | 427 | 784 | 826 | 649 | 496 | 355 | 237 | 224 | 120 | 915 | 1049 | 981 | 625 | 614 | 600 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | cross | cross-on | on | cross | cross-on | cross-on | cross-off | cross-off | cross-on | off | glassy | on | cross-on | cross-on | on | glassy | glassy | on | glassy |
High Tide | 1:57PM2.69m | 2:36AM2.66m | 2:51PM2.94m | 3:19AM2.91m | 3:30PM3.21m | 3:53AM3.17m | 4:04PM3.47m | 4:25AM3.41m | 4:36PM3.70m | 4:57AM3.61m | 5:09PM3.87m | 5:29AM3.77m | 5:43PM3.97m | ||||||||
Low Tide | 8:11PM1.25m | 8:27AM1.23m | 9:00PM0.98m | 9:12AM0.95m | 9:39PM0.70m | 9:48AM0.68m | 10:12PM0.43m | 10:22AM0.43m | 10:45PM0.21m | 10:55AM0.23m | 11:17PM0.05m | 11:29AM0.08m | 11:50PM-0.02m | ||||||||
 | |  | | | | | |  | | | | | | |  |  | | |  | | |
 | 7:50 | — | — | 7:52 | — | — | 7:54 | — | — | 7:54 | — | — | 7:56 | — | — | 7:56 | — | — | 7:58 | — | — |
 | — | 8:06 | — | — | 8:05 | — | — | 8:02 | — | — | 8:00 | — | — | 7:59 | — | — | 7:57 | — | — | 7:54 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — |
Temp °C | 18 | 21 | 19 | 19 | 21 | 19 | 20 | 21 | 20 | 20 | 26 | 23 | 21 | 23 | 19 | 19 | 20 | 19 | 18 | 18 | 18 |
Feels °C | 20 | 21 | 20 | 20 | 21 | 17 | 17 | 19 | 20 | 19 | 24 | 23 | 19 | 20 | 18 | 19 | 20 | 19 | 19 | 18 | 19 |
Swell 1 Height (m) Direction Period (s) | NW 11 | NW 11 | NW 11 | NW 12 | NW 12 | NW 11 | NW 10 | WNW 15 | WNW 14 | WNW 13 | WNW 12 | NW 12 | NW 11 | NW 11 | NW 10 | NW 15 | NW 14 | NW 13 | NW 12 | NW 12 | NW 11 |
| kJ | 652 | 640 | 488 | 478 | 389 | 237 | 173 | 784 | 826 | 649 | 496 | 355 | 237 | 224 | 120 | 915 | 1049 | 981 | 625 | 614 | 600 |
Swell 2 Height (m) Direction Period (s) | — | — | N 5 | — | — | NNW 5 | WNW 16 | NW 11 | — | NNW 4 | NNW 4 | NNW 5 | NNW 5 | NW 14 | NW 13 | WNW 11 | WNW 9 | — | — | — | — |
| kJ | — | — | 18 | — | — | 8 | 427 | 166 | — | 3 | 4 | 13 | 7 | 29 | 84 | 146 | 100 | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | NW 20 | WNW 12 | — | — | — | — | — | — | — | NW 18 | — | — | — | — | — | — |
| kJ | — | — | — | — | — | 15 | 56 | — | — | — | — | — | — | — | 118 | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | W 3 | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 87 | 6 | 12 | 12 | 12 | 12 | 12 | 0 | 0 | 11 | 0 | 0 | 12 | 12 | 12 | 87 | 0 | 0 | 6 | 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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