
Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 21 Jul 2026:
- Best quality surf: Monday 27 Jul, 11PM (local time) - 4.5ft (1.3m), 10s period, NW swell with glassy winds.
- Most powerful swell: Saturday 25 Jul, 5PM (local time) - 8ft (2.5m), 7s period, WNW swell with 687 kJ wave energy.
- Next surfable swell (1★+): Monday 27 Jul, 11PM (local time) - 4.5ft (1.3m), 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 1.3m 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 2.5m 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 (1.3m) 10s |
| Best Surf | 11PM (Mon 27th Jul) | 4.5ft (1.3m) 10s |
| Most Powerful | 5PM (Sat 25th Jul) | 8ft (2.5m) 7s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s look at what’s on the menu for our local stretch. I’ve got to be straight with you – the outlook for Guethary - Les Alcyons/Avalanche is a lean one over the next 16 days. This is a real expert reef setup, and it’s consistent, but the conditions are just not lining up for us.
The water is sitting at a very unusual 78°F – that’s 8°F warmer than normal for this time of year, so you’ll be surfing in a bath.
We start off with a bit of a dud. For Tuesday the 21st and Wednesday the 22nd, the swell is tiny – around 2ft to 3ft – with poor short-period windswell from the NNW. The winds are onshore, so it’s messy and not worth the paddle out. The combined energy is weak, sitting at just 105 on Tuesday morning, dropping to 34 by Wednesday afternoon.
We get a couple of glassy mornings on Thursday the 23rd and Friday the 24th, with the wind going dead calm. The swell is still very small, just 2ft to 3ft, and the period is a weak 6 seconds, so the energy is minimal (32 to 47). It’s pretty, but there’s hardly any push.
Then things get a bit bigger. Saturday the 25th sees a jump in the swell, with a W-WNW windswell building to 6ft in the morning and 8ft in the afternoon. The period is still short (7 seconds), but the energy ramps up significantly, hitting 278 in the morning and a hefty 687 in the afternoon. The problem is the wind is cranking from the W at 18-22 mph, making it a lumpy, cross-onshore mess. The quality is poor, and with that size and those conditions, this is more of a kite-surfing day than a paddle-surfing one. It’s also big enough to be expert-only at 8ft.
The next few days, from Sunday the 26th through to Tuesday the 5th of August, are a real mixed bag of poor surf. The swell drops and rises again, but it’s almost always accompanied by onshore or cross-onshore winds. The energy levels are moderate at best, with a few readings over 200, but the wave comment is consistently “poor.” There’s a brief moment on Monday the 27th where the swell gets a bit of length, hitting a 10-second period from the NW, but the wind is onshore, and the energy is still not translating into quality.
The best of a bad bunch looks like Wednesday the 29th. The morning is glassy with light winds from the N, and the swell is 3ft from the NW at a 9-second period. The energy is a modest 123, and the description says "surfable waves but very ordinary conditions." It’s not a standout, but it’s the only window where the wind is totally clean and there’s a little bit of shape. It’s a small-wave longboarder’s special.
From Thursday the 30th onward, it’s back to poor, small, onshore slop. The energy drops off to weak levels, and the wind never really cooperates.
So, to be honest, there’s no true standout in this window. The best bet is to wait for the glassy morning on the 29th for a tiny, clean session. Otherwise, the picks are thin. The setup might look more interesting for kite surfing on the 25th if you’ve got a big kite.
Rusty out.
Short Range ForecastMostly dry. Warm (max 30°C on Wed afternoon, min 18°C on Wed morning). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 11mm), heaviest on Sat night. Warm (max 26°C on Fri afternoon, min 19°C on Fri morning). Winds increasing (calm on Fri morning, fresh winds from the W by Sat afternoon). | ||||||||||||||||||||
Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | Monday 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) | NNW 7 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 5 | WNW 6 | WNW 7 | WNW 7 | NW 6 | NW 7 | NW 6 | NW 7 | NW 10 | NW 10 | NW 10 |
Wave Graph | |||||||||||||||||||||
93 | 68 | 85 | 35 | 25 | 77 | 38 | 25 | 59 | 29 | 16 | 130 | 278 | 687 | 209 | 178 | 202 | 159 | 170 | 373 | 257 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-off | cross-off | on | cross | glassy | on | cross | glassy | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | on | on | on | cross-off |
High Tide | 10:31AM2.99m | 10:55PM2.98m | 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 | |||||||
Low Tide | 4:32PM0.94m | 5:04AM1.02m | 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 | ||||||||
6:43 | — | — | 6:45 | — | — | 6:46 | — | — | 6:47 | — | — | 6:48 | — | — | 6:48 | — | — | 6:50 | — | — | |
— | — | 9:39 | — | — | 9:38 | — | — | 9:38 | — | — | 9:37 | — | — | 9:37 | — | — | 9:36 | — | — | 9:35 | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 4 | 1 | — | 5 | — | — | — |
Temp °C | 23 | 23 | 22 | 24 | 30 | 26 | 24 | 26 | 24 | 25 | 26 | 22 | 21 | 22 | 22 | 21 | 21 | 21 | 21 | 23 | 22 |
Feels °C | 23 | 21 | 20 | 22 | 27 | 26 | 24 | 26 | 24 | 25 | 25 | 21 | 17 | 18 | 20 | 19 | 19 | 20 | 21 | 23 | 23 |
Swell 1 Height (m) Direction Period (s) | NNW 7 | NNW 6 | NNW 6 | NNW 6 | WNW 10 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 5 | — | — | — | NW 10 | W 10 | NW 12 | NW 7 | NW 7 | NW 10 | NW 10 |
93 | 68 | 85 | 35 | 9 | 77 | 38 | 25 | 59 | 29 | 16 | — | — | — | 4 | 2 | 6 | 159 | 118 | 373 | 257 | |
Swell 2 Height (m) Direction Period (s) | WNW 11 | WNW 11 | WNW 10 | WNW 10 | — | WNW 10 | WNW 10 | WNW 9 | WNW 9 | NW 9 | WNW 9 | — | — | — | — | NW 13 | — | NW 11 | NW 10 | — | — |
12 | 11 | 10 | 10 | — | 9 | 9 | 8 | 8 | 3 | 8 | — | — | — | — | 7 | — | 43 | 170 | — | — | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | NNW 6 | — | — | — | — | — | WNW 3 | WNW 6 | WNW 7 | WNW 7 | NW 6 | NW 7 | NW 6 | — | — | — | — |
— | — | — | — | 25 | — | — | — | — | — | 4 | 130 | 278 | 687 | 209 | 178 | 202 | — | — | — | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 69 | 87 | 2 | 1 | 197 | 17 | 1 | 196 | 17 | 84 | 304 | 177 | 539 | 1158 | 297 | 147 | 837 | 136 | 12 | 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.










