Surf forecastSpot statisticsHistorical report

Rhossili Bay seasonal overview

Best Surf Season (October - March)

The North Atlantic awakens in October, and by November the Gower Peninsula is firmly in the firing line. With average wave heights pushing above 1.2m and periods climbing into the 9-10 second range, these months deliver the most consistent swell of the year. The dominant westerly and south-westerly swell trains – perfectly aligned with Rhossili’s SSW exposure – produce powerful, long-period surf that can range from punchy 1-1.5m fun to pumping 2.5m+ XL beasts when deep Atlantic lows stall west of Ireland. The catch? Onshore winds from the same direction often accompany these storms, making clean conditions a gamble. However, when a high-pressure ridge sets up over Scandinavia, the offshore N-NE flow creates glassy, lined-up waves that make the long walk to the water well worth it. This is the prime window for size and power, especially December through February.

Fair Surf Season (April, September)

The transitional months of April and September offer a more mixed bag. Average swell heights drop to 0.9m and periods shorten to the 8-9 second range, but there’s still enough energy from the SW-W swell window to produce rideable waves for the majority of days. The ideal wind frequency holds at a moderate 7-11%, and with weaker wind speeds overall, windows of cleaner conditions can align with small to moderate swell. April sees the last of the winter swell while September hints at the coming autumn ramp-up. These are great months for loggers, mid-lengths, and anyone who prefers a more manageable, less crowded lineup – just keep an eye on those pesky onshore troughs.

Low Surf Season (May - August)

Summer brings the Gower’s infamous ‘flat spell’. From May through August, average swell heights languish around 0.7-0.8m with periods rarely exceeding 8 seconds. The dominant swell direction remains WSW-W, but the energy is minimal and often overpowered by thermal-driven onshore breezes. Ideal offshore wind frequency drops to a paltry 6-8%, meaning most days are plagued by bumpy, messy conditions. While the occasional rogue south-westerly groundswell can sneak in, the lack of consistent North Atlantic storm activity and the prevalence of high pressure over the UK make this the quietest period. For the dedicated surfer, a foam board or a summer trip to the South Atlantic is a better bet. Still, Rhossili’s beauty and the occasional small grovel session on a glassy dawn can provide a few moments of joy.

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Conditions at Rhossili Bay in September

September: Autumn Awakening

September is the turning point. The average swell height rises to 0.9m and the period increases to 8.1s. The swell window is still WSW (36.7%) and W (24.6%), but the proportion of waves in the 0.5-1.5m range grows. The ideal wind frequency remains low at 7%, but the wind speeds begin to pick up again, and there are more days with offshore N-NE flow. The increasing storm activity in the North Atlantic sends the first solid pulses of groundswell towards the UK. When these align with a clearing high pressure, Rhossili can deliver clean, shoulder-high waves with enough power for grovel turns. It’s a transitional month – expect variability, but be ready to jump when the window opens.

Average Spot conditions at Rhossili Bay in September

Swell history for September

0 - 0.5
0.5 - 1
1 - 1.5
1.5 - 2.0
2.0 - 2.5
> 2.5 m

Wind history for September

0 - 10
10 - 20
20 - 30
30 - 40
40 - 50
> 50 km/h

Swell quality

Analyze the groundswell consistency at Rhossili Bay during September. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at Rhossili Bay for your next trip in September.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Rhossili Bay for September. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at Rhossili Bay.

Swell with good wind

Swell with good wind by size