CatchWindow fishing intelligence

Tokyo Bay, Japan Daily Water Report — October 5, 2026

Tokyo Bay is a strong sailing day and a generally workable harbor day, but the northerly breeze makes it less forgiving for small, lightly loaded craft than the scores alone might suggest. Sailing leads at 8.6/10, with boating 7.7 and diving 8.4; kayaking is a respectable but more conditional 6.7. These are suitability estimates, not safety clearances. The useful window is early: dawn arrives at 05:14, sunrise is 05:39, and the lightest seas occur around midnight, with the day’s calmest wave height near 0.38 m. Through the morning, waves remain modest at roughly 0.4–0.5 m, though the short 0.42 m wind-wave component at 2.4 seconds can make the surface feel busier than the headline height suggests. A north wind around 11 knots, gusting to 18, is enough to give sailboats something to work with while asking paddlers to keep their route, return leg, and exposure honest. For anglers, the 5.8/10 rating is middling rather than miserable. The better timing is the 06:51–08:51 solunar major period, with a smaller opportunity from 13:21–14:21. Pressure is falling from a representative 1011 hPa, and no tide data are available, so avoid pretending the clock has all the answers. Fishing scored better in the reconstructed CatchWindow history over the previous two days, at 6.9 and 7.4, when pressure was higher and winds lighter. Divers get warm water by October standards: marine SST is 22.6 C, while the supplied SST reading is 23.7 C, about 1.3 C above average. Surface conditions support the 8.4 diving score, but atmospheric visibility near 31.9 km is not an underwater-visibility report. The 0.22 m swell has a long 10.6-second period, so assess actual entry and exit conditions on site. Expect the gustiest stretch near 15:00, when gusts may reach 18.7 knots. A brief rain window is indicated around noon, though representative precipitation is zero. By late afternoon, dusk is 17:47; the evening solunar major period runs 18:51–20:51, after dark. The next two days stay breezy with 0.4–0.6 m waves possible, then conditions ease markedly from October 8 onward, with 0.2–0.3 m seas and lighter winds by the 9th. Best bet: rig early, sail the morning breeze, and leave yourself plenty of harbor for the gusty afternoon.