
Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 22 Jul 2026:
- Best quality surf: Monday 27 Jul, 11PM (local time) - 4.5ft (1.4m), 10s period, NW swell with glassy winds.
- Most powerful swell: Saturday 25 Jul, 5PM (local time) - 8ft (2.4m), 7s period, WNW swell with 590 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 11PM (local time) - 4.5ft (1.4m), 10s 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 (Jul 27) at 11PM. The primary swell is predicted to be 1.4m and 10s 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 2.4m 7s and forecast to arrive on Saturday (Jul 25) at 5PM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Mon 27th Jul) | 4.5ft (1.4m) 10s |
| Best Surf | 11PM (Mon 27th Jul) | 4.5ft (1.4m) 10s |
| Most Powerful | 5PM (Sat 25th Jul) | 8ft (2.4m) 7s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get into it. We’re looking at a pretty grim stretch ahead for the Guethary area, specifically Les Alcyons/Avalanche. This is an expert-only reef break, so don’t even think about it if you’re still finding your feet.
Right off the bat, the water is sitting at a very warm 77°, and that’s 7° warmer than what’s normal for this time of year – that’s a serious anomaly. The ocean is feeling tropical.
For the first few days, there’s just nothing to get excited about. The swell is tiny, under 3ft, with a short, weak period, and the wind is either onshore or cross-onshore, messing up any chance of a clean wave. The combined energy is pathetic, reading in the 30s and 40s. It’s not worth paddling out.
We hit a bit of juice on Saturday the 25th, with the swell picking up to 6ft in the morning and 8ft in the afternoon, but it’s coming from the WNW with a short 7-second period. The energy is moderate (260 in the morning, 590 in the afternoon), but the wind is howling 15-18 mph cross-onshore. That’s lumpy, choppy, and messy. This is more kite-surfing territory than a clean paddle session.
The first real glimmer of hope comes on Tuesday the 28th. The morning is glassy, with a clean 4ft swell from the NW, a solid 10-second period, and moderate energy (273). The wind is glassy from the ENE. That’s your best window in the early part of the outlook. Get in the water early, because the afternoon turns cross-onshore and choppy.
The next standout is a long way off, but it looks promising. On Tuesday the 4th of August, the morning is glassy again with a 4ft NW swell, and the energy is moderate (115). The afternoon is where it gets interesting: the wind turns offshore from the SE at 9 mph, the swell bumps up to 4ft from the WNW, and the period jumps to 11 seconds. The energy is moderate (375) and the conditions are clean. That’s a solid afternoon session.
Finally, Wednesday the 5th of August has a glassy morning with a clean 4ft swell from the WNW, a 10-second period, and moderate energy (340). It’s another good window, but the afternoon turns onshore again.
So, the honest truth? This is a long, dry spell with two very specific windows that are worth your time. The best of the bunch is the afternoon of Tuesday the 4th of August. Offshore wind, clean lines, and a decent swell. The morning of Tuesday the 28th is your other shot. Everything else is a write-off. It’s a reef, so the long-period groundswell on the 4th (11 seconds) will wrap in nicely, but remember, it’s an expert wave. The crowds are often there, but with this forecast, you might have it to yourself.
Rusty.
Short Range ForecastMostly dry. Warm (max 25°C on Wed afternoon, min 18°C on Wed morning). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 13mm), heaviest on Sat night. Warm (max 22°C on Sat afternoon, min 18°C on Mon night). Winds decreasing (fresh winds from the W on Sat afternoon, calm by Mon night). | ||||||||||||||||||||
Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | Monday 27 | Tuesday 28 | |||||||||||||||
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) | NNW 6 | N 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | WNW 4 | WNW 6 | WNW 7 | WNW 7 | NW 7 | NW 7 | NW 7 | NW 7 | NW 10 | NW 10 | NW 10 | NW 10 | NW 10 | NW 10 |
Wave Graph | |||||||||||||||||||||
35 | 23 | 61 | 35 | 30 | 47 | 17 | 11 | 188 | 257 | 590 | 452 | 331 | 247 | 169 | 408 | 441 | 334 | 273 | 279 | 268 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross | on | on | cross | on | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross-on | glassy | glassy | cross-on | cross |
High Tide | 11:27AM2.83m | 11:58PM2.77m | 12:35PM2.74m | 1:13AM2.67m | 1:48PM2.75m | 2:26AM2.70m | 2:52PM2.86m | 3:24AM2.81m | 3:43PM3.02m | 4:10AM2.97m | 4:26PM3.21m | 4:49AM3.12m | 5:03PM3.39m | ||||||||
Low Tide | 5:33PM1.14m | 6:05AM1.20m | 6:43PM1.24m | 7:14AM1.27m | 7:55PM1.23m | 8:20AM1.23m | 8:57PM1.11m | 9:16AM1.10m | 9:48PM0.94m | 10:02AM0.93m | 10:31PM0.76m | 10:42AM0.75m | 11:09PM0.59m | ||||||||
6:45 | — | — | 6:46 | — | — | 6:47 | — | — | 6:48 | — | — | 6:48 | — | — | 6:50 | — | — | 6:50 | — | — | |
— | — | 9:38 | — | — | 9:38 | — | — | 9:37 | — | — | 9:37 | — | — | 9:36 | — | — | 9:35 | — | — | 9:34 | |
mm | — | — | — | — | — | — | — | — | — | — | — | 5 | 1 | 1 | 4 | 2 | — | — | — | — | — |
Temp °C | 22 | 25 | 24 | 23 | 25 | 24 | 23 | 24 | 22 | 21 | 22 | 21 | 21 | 22 | 21 | 21 | 22 | 21 | 25 | 32 | 29 |
Feels °C | 21 | 23 | 24 | 23 | 25 | 25 | 23 | 24 | 21 | 18 | 18 | 18 | 19 | 20 | 20 | 23 | 22 | 21 | 26 | 31 | 31 |
Swell 1 Height (m) Direction Period (s) | NNW 6 | N 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 5 | — | W 12 | — | — | — | NW 12 | NW 7 | NW 10 | NW 10 | NW 10 | NW 10 | NW 10 | NW 10 |
35 | 23 | 61 | 35 | 30 | 47 | 17 | 9 | — | 3 | — | — | — | 6 | 169 | 408 | 441 | 334 | 273 | 279 | 268 | |
Swell 2 Height (m) Direction Period (s) | WNW 10 | WNW 10 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | NW 7 | WNW 9 | — | — | — | — | — | — | NW 11 | — | — | — | — | — | — |
10 | 9 | 9 | 9 | 8 | 8 | 11 | 8 | — | — | — | — | — | — | 31 | — | — | — | — | — | — | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | W 3 | — | WNW 9 | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
— | — | — | — | 1 | — | 8 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | — | WSW 3 | — | — | — | WNW 4 | WNW 6 | WNW 7 | WNW 7 | NW 7 | NW 7 | NW 7 | — | — | — | — | — | — | — |
— | — | — | 2 | — | — | — | 11 | 188 | 257 | 590 | 452 | 331 | 247 | — | — | — | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 7 | 197 | 17 | 31 | 196 | 17 | 537 | 12 | 12 | 1158 | 147 | 147 | 1044 | 12 | 11 | 87 | 0 | 0 | 11 | 12 | |
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.










