Belharra seasonal overview
Best Surf Season (October - March)
Belharra is a spot built by the North Atlantic. From October through March, the storm track is aimed like a cannon at the Bay of Biscay, with deep extratropical lows rolling east-northeast and firing long-period NW and WNW groundswell into this exposed NNW-facing reef. Average wave heights sit between 5-7ft (1.6-2.1m) on the buoy, with periods in the 11-13s range, and the climatological frequency of offshore S/SSW winds jumps to 35-39%. This is the window when Belharra's unique bathymetry lights up: long, heavy, powerful waves with clean, groomed faces. December, January, and February are the crown jewels, with November and March close behind. When the NAO drops and the jet stream buckles over the eastern Atlantic, these months can produce multiple XL swells in a single week.
Fair Surf Season (April, May and September)
The shoulder months are for the patient. April still sees plenty of NW swell, but average periods dip to 10-11s and ideal wind days drop to about 26%. May and September are transitional: swell direction remains remarkably consistent from the NW, but wave heights fall to around 4ft (1.2-1.3m) and periods drop below 10-10.5s. You can find clean, rippable conditions when a late-season low pressure stalls in the Bay or a north Atlantic depression scrapes past, especially with early morning S/SSW winds. But the consistency and firepower of winter are missing, and onshore NW seabreezes often chop the surface by midday.
Low Surf Season (June - August)
Summer is the doldrums for Belharra. The North Atlantic high pressure builds and the storm track retreats to Iceland, leaving the Bay of Biscay under a persistent NW/NNW wind regime that blows directly onshore at this spot. Average swell heights bottom out around 3ft (1.0m) with periods of 8.8-9.2s - short-period, local windswell rather than true groundswell. Ideal S/SSW offshore wind days drop to 14-17%. The water is warmest at 21-23°C, but unless a rare tropical system or cut-off low drifts south, the reef stays small and bumpy. For big-wave chargers, this is the season to rest, repair boards, and watch the charts.