Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 12 Aug 2026:
- Most powerful swell: Sunday 16 Aug, 8PM (local time) - 4.5ft (1.3m), 8s period, NW swell with 205 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 1.3m 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) | 4.5ft (1.3m) 8s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Right then, let’s have a look at what’s coming up for Guethary - Les Alcyons/Avalanche. This is a reef setup that takes a good W swell, so it’s got the bones for something special, but we’ve got a long wait ahead of us. The water is sitting at 76°F right now, which is much warmer than normal for this time of year – 4°F above average, so it’s a real treat if you’re in the water.
First thing to say is, there’s nothing worth paddling out for in the immediate future. We’ve got a solid gap from now until the morning of Friday the 21st of August where the surf is just flat or blown out. The next week and a bit is a write-off – tiny swell, poor surf conditions, and mostly onshore or cross-onshore winds. Not a single recommendation in that stretch.
Then, on Friday morning the 21st of August, we finally get a glimmer. The wind goes glassy out of the east, and the swell picks up to 3 ft from the NNW, with a period of 9 seconds. The combined energy jumps to 231 (moderate), and the forecast says expect good surf conditions. This is the only standout in the whole 16-day window. It’s small, clean, and glassy – perfect for a longboard or a funboard if you’re keen to get wet without getting thumped. The swell direction is a bit off the optimum W, but with that glassy morning, it’s the best you’ll get.
After that, it’s a bit of a mixed bag. The afternoon of the 21st turns onshore, and Saturday the 22nd is cross-onshore with rain showers. Sunday the 23rd has another glassy morning, but swell drops to 3 ft from the NW with a short period of 8 seconds. The energy is weak at 99, and the surf is still rated poor. Not great.
The last chance comes on Thursday morning the 27th of August – glassy again, calm wind, and a 4 ft NW swell with a 9-second period. The combined energy is a solid 314 (moderate), and the forecast says expect good surf conditions. This one is promising, but it’s a long way out, so take it with a pinch of salt. The swell direction is NW, which isn’t the optimum W, but when it’s glassy and head-high, you won’t complain.
So, the only real standout is that Friday morning the 21st of August. If you can wait out the dead spell, that’s your window. The Thursday the 27th morning is also worth keeping an eye on, but it’s less certain.
Rusty.
Short Range ForecastLight rain (total 3mm), mostly falling on Fri night. Warm (max 27°C on Wed afternoon, min 20°C on Fri morning). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 4mm), mostly falling on Sat night. Warm (max 23°C on Sat afternoon, min 20°C on Mon morning). Wind will be generally light. | |||||||||||||||||||
Wed 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | ||||||||||||||
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) | WNW 10 | WNW 9 | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | WNW 8 | NW 8 | NW 8 | NW 8 | NW 7 | NW 7 | NW 7 | NW 7 | NW 6 | NNW 6 | NW 6 |
Wave Graph | ||||||||||||||||||||
34 | 28 | 50 | 32 | 93 | 111 | 74 | 75 | 71 | 64 | 126 | 129 | 177 | 137 | 97 | 109 | 63 | 33 | 20 | 15 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | glassy | on | cross | cross-on | on | cross-on | on | on | on | cross-on | on | on | on | on | cross-on | cross-on | on | glassy |
High Tide | 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 | 8:54AM3.28m | 9:13PM3.21m | |||||||
Low Tide | 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 | 2:57PM0.65m | 3:21AM0.82m | |||||||
— | — | 7:07 | — | — | 7:09 | — | — | 7:09 | — | — | 7:11 | — | — | 7:11 | — | — | 7:13 | — | — | |
— | 9:14 | — | — | 9:13 | — | — | 9:12 | — | — | 9:09 | — | — | 9:08 | — | — | 9:07 | — | — | 9:06 | |
mm | — | — | — | — | — | — | — | 3 | — | — | 2 | 2 | — | — | — | — | — | — | — | — |
Temp °C | 27 | 25 | 25 | 27 | 24 | 22 | 24 | 23 | 22 | 23 | 22 | 21 | 22 | 22 | 21 | 22 | 21 | 21 | 22 | 21 |
Feels °C | 29 | 28 | 28 | 29 | 25 | 24 | 26 | 25 | 23 | 24 | 24 | 23 | 22 | 23 | 21 | 21 | 22 | 21 | 21 | 22 |
Swell 1 Height (m) Direction Period (s) | NW 8 | WNW 9 | W 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | NW 5 | WNW 8 | NW 8 | NW 8 | NW 8 | NW 7 | NW 8 | NW 7 | NW 7 | NW 6 | NNW 6 | NW 6 |
28 | 28 | 50 | 32 | 93 | 111 | 74 | 75 | 22 | 64 | 126 | 129 | 177 | 137 | 18 | 109 | 63 | 33 | 20 | 15 | |
Swell 2 Height (m) Direction Period (s) | WNW 10 | NW 8 | NW 7 | WNW 12 | NW 6 | — | — | NW 4 | WNW 9 | — | — | — | — | — | — | — | W 11 | NW 9 | NW 7 | WNW 8 |
34 | 20 | 7 | 30 | 2 | — | — | 15 | 71 | — | — | — | — | — | — | — | 2 | 3 | 7 | 11 | |
Swell 3 Height (m) Direction Period (s) | — | — | NNW 4 | NNW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | WNW 8 | — |
— | — | 1 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | — | |
Wind waves Height (m) Direction Period (s) | — | — | W 3 | — | WNW 3 | NW 4 | NW 4 | WSW 4 | — | NW 6 | — | — | — | — | NW 7 | — | — | — | — | — |
— | — | 1 | — | 3 | 3 | 6 | 4 | — | 39 | — | — | — | — | 97 | — | — | — | — | — | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 197 | 31 | 1 | 196 | 17 | 196 | 196 | 72 | 197 | 87 | 197 | 136 | 12 | 12 | 136 | 87 | 43 | 224 | 597 | 274 |
Best forecast wave conditions in La Cote Basque | ||||||||||||||||||||
Best forecast wave conditions in France | ||||||||||||||||||||
Header Global | ||||||||||||||||||||
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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.











