CatchWindow fishing intelligence

Tokyo Bay, Japan Daily Water Report — August 28, 2026

Diving is the standout call today, with an 8.1 out of 10, thanks to a rare combination of calm surface conditions and water clarity that will put you on the fish you hope to see. The representative wind sits at 9 knots from the south, gusting to 17, but the real story is the wave energy—a mere 0.38 meters at a sluggish 5.3-second interval. That’s flat enough to keep the surface manageable for entry and exit all day, though the mid-morning light will hit its peak UV index near 5, so plan your bottom time around the sun's angle if you’re shooting photos. Sea surface temperature holds at 27.7 degrees Celsius, a full 1.7 degrees warmer than the long-term average, which should extend your comfort zone without demanding a thick suit. The full moon overhead—100 percent illuminated and rising at 18:08—pulls a solunar major window from 11:00 to 13:00, so if you’re mixing in a rod, the fishing score of 6 reflects that the timing aligns better than the bite itself might suggest. Sailing earns a solid 7.7; the southerly breeze is consistent enough to fill sails without overpowering, though the cloud cover at 85% will keep the deck from baking under the August sun. Boating sits at 6.8, with the 0.8-meter-per-second current pushing toward 315 degrees, meaning a northwest drift you’ll need to factor into any anchor or trolling plan. Compared to recent days, today’s diving remains in the same elite tier as yesterday’s 8 and the 8.2 from the 23rd, but the wind is a few knots higher than that near-calm stretch, so the surface won’t be a glass mirror. Surfing scores a mediocre 4.8; the swell comes from 198 degrees at 4.2 seconds, which is too short and weak to break with any purpose along most shorelines, even with the low southerly component. The pressure is rising from 1006.8 to 1010.3 millibars, a stabilizing signal that suggests this wind won’t build into the afternoon squall line you sometimes get in late August. Over the next few days, the pattern looks to quiet down further: Saturday brings wave heights dropping to 0.1-0.4 meters and a 100% chance of rain, so diving windows will narrow, while Sunday and Monday offer laps of near-flat conditions under a lighter breeze. For the best bet today, slide into the water during the solunar major around midday and let the warm current carry you northwesterly while the surface stays calm enough to see your own bubbles rise.