Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 11 Aug 2026:
- Most powerful swell: Sunday 16 Aug, 8PM (local time) - 3.5ft (1.1m), 8s period, NW swell with 141 kJ wave energy.
Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.1m 8s and forecast to arrive on Sunday (Aug 16) 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+) | - | - |
| Best Surf | - | - |
| Most Powerful | 8PM (Sun 16th Aug) | 3.5ft (1.1m) 8s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here with the full lowdown on the coming weeks at our spot.
We’re in for a bit of a slow start, I won’t lie. The first stretch from Tuesday the 11th right through to Monday the 24th of August looks pretty quiet. There’s a long gap where the surf is just too small and weak to get excited about. The energy in the water is low, with readings mostly under 100 (weak) and never breaking into anything really solid. The swell is hanging around 1 ft to 3 ft from the NW and WNW, with short periods mostly under 8 seconds, so the waves are just lacking any push. The wind is onshore or cross-onshore most of this time, which doesn’t help. It’s not until around Wednesday the 19th that we start to see the swell nudge up to 5 ft, but the quality is still poor or marginal. The water temperature at the start is 75°, which is much warmer than normal for this time of year, so that’s something to note.
Now, the real standout window arrives on Monday the 24th of August. That’s the day we’ve been waiting for. Monday morning at Guethary - Les Alcyons/Avalanche is the pick of the entire forecast. We’re looking at a clean 8 ft swell from the NW with a period of 9 seconds, and the wind is completely calm, making it glassy. The combined energy is strong at 882. This is an expert-level reef break, and while it’s often crowded, the conditions are set to be excellent. The swell direction is from the NW, which is spot on for this exposed reef. If you’re an experienced surfer, mark that Monday morning in your calendar.
Tuesday the 25th is also a beauty. Another glassy morning with a 8 ft NW swell, period of 10 seconds, and that calm wind again. The energy is very strong at 1077. This is excellent for experienced surfers, but the afternoon turns onshore, so get out early. The water is still feeling much warmer than normal, which is a bonus.
Beyond that, things start to drop off again through the week, with a few smaller, choppier days. The period for the standout days is around 9-10 seconds, which is a decent groundswell – it’ll have a bit of shape and energy, but those longer gaps between sets will make paddling out a bit easier.
So, my advice: be patient through the first couple of weeks, and save your energy for that Monday the 24th and Tuesday the 25th. That’s where the magic is.
Rusty
Short Range ForecastMostly dry. Warm (max 29°C on Wed afternoon, min 20°C on Thu night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 5mm), mostly falling on Fri night. Warm (max 23°C on Fri afternoon, min 20°C on Mon morning). Wind will be generally light. | |||||||||||||||||||
Tue 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | ||||||||||||||
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 9 | NW 8 | NW 8 | WNW 10 | WNW 9 | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | NNW 7 | NW 7 | NW 7 | NW 8 | NW 7 | NW 7 | NW 7 | NW 7 |
Wave Graph  | ||||||||||||||||||||
 kJ | 59 | 55 | 44 | 34 | 28 | 50 | 32 | 93 | 77 | 74 | 66 | 71 | 70 | 97 | 84 | 111 | 69 | 75 | 64 | 63 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | cross-on | glassy | cross-on | cross | on | on | cross-on | on | on | cross-on | on | on | glassy | cross-on | on | cross-on | cross-on | on | cross |
High Tide | 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 | 7:40AM3.68m | 7:56PM3.82m | 8:17AM3.50m | 8:34PM3.53m | |||||||
Low Tide | 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 | 1:36PM0.16m | 2:03AM0.24m | 2:16PM0.38m | 2:41AM0.52m | |||||||
 |  | | | | | | | |  |  |  | |  | | | | | |  | |
 | — | — | 7:07 | — | — | 7:07 | — | — | 7:09 | — | — | 7:09 | — | — | 7:11 | — | — | 7:11 | — | — |
 | — | 9:15 | — | — | 9:14 | — | — | 9:13 | — | — | 9:12 | — | — | 9:09 | — | — | 9:08 | — | — | 9:07 |
mm | — | — | — | — | — | — | — | — | — | — | 1 | — | — | 3 | — | — | 1 | — | — | — |
Temp °C | 25 | 24 | 25 | 29 | 25 | 24 | 26 | 23 | 22 | 23 | 22 | 22 | 23 | 22 | 21 | 23 | 22 | 22 | 23 | 22 |
Feels °C | 26 | 27 | 28 | 30 | 28 | 26 | 27 | 24 | 23 | 24 | 23 | 24 | 24 | 23 | 23 | 25 | 23 | 23 | 23 | 23 |
Swell 1 Height (m) Direction Period (s) | NW 9 | NW 8 | NW 8 | NW 8 | WNW 9 | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | NW 6 | NNW 7 | NW 7 | NW 7 | NW 8 | NW 7 | NW 7 | NW 7 | NW 7 |
| kJ | 59 | 55 | 44 | 28 | 28 | 50 | 32 | 93 | 77 | 74 | 66 | 31 | 70 | 97 | 84 | 111 | 69 | 75 | 64 | 63 |
Swell 2 Height (m) Direction Period (s) | — | WNW 10 | WNW 11 | WNW 10 | NW 8 | NNW 4 | WNW 12 | NW 6 | — | — | — | WNW 9 | WNW 8 | — | — | — | NW 8 | — | — | W 8 |
| kJ | — | 9 | 12 | 34 | 9 | 1 | 30 | 1 | — | — | — | 71 | 61 | — | — | — | 34 | — | — | 1 |
Swell 3 Height (m) Direction Period (s) | — | W 13 | — | — | — | NW 7 | NW 7 | — | — | — | — | — | — | — | — | — | — | — | — | W 11 |
| kJ | — | 3 | — | — | — | 7 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | 2 |
Wind waves Height (m) Direction Period (s) | NNW 4 | — | — | — | NW 3 | W 3 | NW 4 | WNW 3 | WNW 4 | NW 4 | NW 6 | — | — | — | — | — | — | — | — | — |
| kJ | 2 | — | — | — | 2 | 1 | 4 | 5 | 5 | 9 | 25 | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 197 | 17 | 1 | 356 | 47 | 17 | 196 | 17 | 136 | 220 | 17 | 136 | 197 | 1 | 136 | 87 | 31 | 196 | 87 | 17 |
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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