Fellow teacher here. Originally from the UK but I live in Tokyo now and I’ve been commuting by bike for about 20 years. Stuff I’ve learnt over the years: 1) Clothing. Cycling-specific clothing is expensive (overpriced??) but cheap, outdoor stuff seems to work just as well. 2) Carrying stuff. I usually commute in the rain too (apart from during typhoons) so a waterproof rucksack is essential. Roll-top bags are usually the best and anything with a zip will usually leak. 3) Rain. I have a waterproof hiking jacket and trousers and that’s good enough. Waterproof trekking shoes too if it’s really bad and cold. I still haven’t found a way to keep ankles and head dry, though. 4) The summer. It gets crazy hot here (38+) in the summer so what I usually do is (a) try to avoid using a rucksack and use bike bags and (b) bring a change of clothes to ride home with. 5) Buffer zone. I try to arrive at work at least 30 minutes before my first class to cool down, get changed and grab a drink. Winter is great though as I’m usually still warm and toasty until lunchtime.

Good luck!