Interesting question Dick!
What I always consider to be the official "start" of the harvest season is the "Ta-agari" hinpyoukai or show held in Mushigame. It's held most often on the first or second Sunday in Sept. and is a display of some of the smaller. prettier koi that breeders pull up early.
You won't start to see the ditches "swell" until the middle half of next month. Possibly even later as we've had an unusually warm summer this year, and we're still experiences record temperatures in many places throughout the country.
Niigata is always at risk from sudden weather changes due to the mountain range that straddles Niigata and Gunma prefectures in the south. If there is a cold snap and moist are from the Sea of Japan blows in, it generally gets stuck on the Niigata side and you get snowfall Shiozawa through and beyond Yamakoshi. I've not heard of any predictions for a cold winter, but haven't really been on the lookout either. Hope there's not a repeat of what we experienced during the ZNA All-Japan two years ago. Mike and I were very close to being stranded on the highway about 35 miles from Ojiya! :cry: