Oregon Coast Enters Fall Transition Under This Week's Full Moon

What's next

Expect the temperature gap between open coast and river-mouth water to persist through the weekend. The Astoria reading typically cools toward the ocean number as freshwater influence eases into fall, so watch for that spread to narrow over the next several days.

The spring tide cycle tied to tonight's full moon peaks over the next two to three days, producing the strongest exchanges of the month. It's worth building trips around the slack-water transitions at the jetties and bay mouths where current concentrates bait and predators alike.

With the equinox behind us and days shortening fast, this is the seasonal window when Oregon's nearshore and estuary conditions shift week to week rather than staying static, so a reading checked today is worth rechecking again by midweek.

Context

Late September sits squarely in Oregon's fall transition, when upwelling winds typically ease, river discharge patterns begin to shift, and estuary and ocean temperatures start converging after summer's wider spread. The current gap between the South Beach and Astoria readings tracks a normal seasonal pace for this time of year, neither notably early nor late.