Yokohama weather in September

September looks decent and is a gamble: the first half is still summer humidity, and typhoon season peaks now. I've had a perfect week and I've had two days indoors watching trains cancel. Late September is safer than early.

Forum posters consistently describe November as one of the driest months in Japan, making it excellent for sightseeing and walking around Yokohama - one visitor reported temperatures starting in the 20sC early in the month and dropping into the teens by month's end, with just a handful of drizzly days and nothing torrential across the whole stretch. Posters comparing October and November describe November as slightly cooler but drier, with the added draw of autumn foliage coming into its own. Posters generally recommend layering for the temperature drop as the month progresses, since a trip spanning early to late November can feel like two different seasons. Posters generally rate November as one of the best overall months to visit Yokohama.

Japan-forum regulars call May one of the best windows to visit the greater Tokyo/Yokohama area - it's before the rainy season, which typically doesn't arrive until around June 7-10. The catch is that May itself is changeable: posters describe stretches of 3 sunny days followed by a day or two of rain, and by late May it can turn briefly hot and humid before settling back down. The standard advice is to pack for everything - short sleeves, a long-sleeve layer, a light jacket and a compact rain parka. For Yokohama itself, the Minato Mirai waterfront and Sankeien Garden are the most-recommended stops, and it's called worth a full day beyond a quick side trip from Tokyo.