Cardiff Reef - surf spot statistics

Best Surf Season (October - March)

The North Pacific comes alive during these months, generating consistent, long-period swell from the W and WSW that pours into Cardiff Reef. With an average wave period of 12-13 seconds and heights sitting in the fun to solid range (1-1.5m), the reef pulses with powerful, rideable waves. The real key, though, is the wind: offshore flow from the NE to ESE quadrant blows clean 22-50% of the time, sculpting glassy faces and making the most of every set. When a strong Aleutian low parks itself in the Gulf of Alaska, we see those epic, pumping days with waves in the 1.5-2.5m range. This is prime time — cold water, big skies, and consistent action.

Fair Surf Season (April & September)

These shoulder months are a mixed bag, as the swell pattern transitions. April still gets a decent dose of W and WSW swell (average 1.1m, 13.3s period), but the offshore wind window narrows to just 16%. You’ll often find a morning window with a light ENE breeze, but by mid-day the onshore flow kicks in. September sees the tail end of summer south swells from the SSW and SW, with average heights around 1m and very long periods (13.6s). However, ideal offshore winds are rare — only 6% of the time. When the stars align, those long-period ground swells combine with a morning offshore — that’s when you score clean, peeling lines.

Low Surf Season (May - August)

Summer brings a dramatic shift: the dominant swell shifts to the SSW and SW, primary from Southern Hemisphere storms and local eddies. While wave periods remain long (13.5-13.8s), the heights are small — averaging just 1.0m or less, most of it in the 0.5-1.5m fun-sized range. The real problem is the wind: offshore flow plummets to 1-4%, meaning the prevailing west to southwest winds (onshore) chop up the wave faces 90% of the time. Occasional early morning glass-offs with a light easterly can offer short windows, but overall it’s a struggle. Look for grindy small-wave boards and hope for a rare tropical storm pulse to break the monotony.

September: Signs of Life, But Puny

September sees a slight uptick in consistency, but conditions remain challenging. Swell is still dominated by SW (42%) and WSW (34%), with a growing SSW component (16%). Average height returns to 1.0m, and period stays long at 13.6s. The biggest issue remains the wind — ideal offshore only occurs 6% of the time. Onshore W and WNW winds blow 52% of the time, often moderate. However, the changing season brings occasional early morning ENE or E offshore breezes (around 2% combined) that offer short windows of clean, small waves. The first hints of winter W swell start to appear in the data (7.6% of swell from W). This is a month of patience — the potential for good surf exists, but you have to be ready to pounce on those rare, clean moments.