Surf forecastStatisticsHistorical report

Osbourne seasonal overview

Best Surf Season (October – March)

The heart of winter delivers the most consistent and powerful swell to Osbourne. Average wave heights hover around 1.6–1.7 m with periods often reaching into the 8.6–8.7 s range, thanks to frequent extratropical cyclones tracking across the North Atlantic. These systems generate significant long‑period groundswell that can light up the east‑southeast facing beach. However, the offshore wind window (W‑NNW) is only open about 25 % of the time, so quality sessions are a game of patience. When a cold front passes and the wind swings west, the waves become clean, hollow and absolutely pumping.

Fair Surf Season (April – June & September)

Spring and early autumn offer a trade‑off: smaller but more rideable waves and a slightly higher chance of offshore breezes. April averages 1.4 m at 8.4 s, while September sees 1.2 m at 8.5 s. Wind‑favorable conditions occur 28–37 % of the time, making these months the most reliable for fun, rippable waves. Swell direction shifts south as the jet stream weakens, and while the dominant S‑SSW energy isn’t ideal, it still produces workable lines. Longboarders and shortboarders alike find plenty of fun‑sized surf.

Low Surf Season (July – August)

Summer brings the smallest surf of the year. Average wave heights drop to just 1.0 m with periods of 7.2–7.7 s – often choppy and groveling. Although the offshore wind clock ticks up to 41–45 % (the highest of any season), the swell is simply too weak to light up the spot in a meaningful way. Occasional tropical systems can inject a rare pulse of energy, but most days are best reserved for a paddle or a flat‑day session.

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Conditions at Osbourne in September

September: Turning the Corner

September marks a noticeable shift. Average swell rebounds to 1.2 m with a period of 8.5 s – fun‑sized and starting to get punchy. Swell energy is still largely S (19.0 %) and SSW (18.6 %), but optimal E‑SSE rises to 42.3 % as hurricane‑generated groundswell begins to arrive. Offshore wind odds are a solid 37 %, with SW (15.7 %) and WSW (11.0 %) still common but occasionally mixing with WNW‑NW flow (WNW 7.1 %, NW 6.5 %). The combination of building swell and fair wind makes September a prime month for rippable waves. Long‑period pulses from distant hurricanes can push well into the 1.5‑2 m range – a taste of the winter to come.

Average Spot conditions at Osbourne 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 Osbourne 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 Osbourne for your next trip in September.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Osbourne 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 Osbourne.

Swell with good wind

Swell with good wind by size