I'm in Tokyo right now. The weekend has been pretty warm. Very sunny but the nights turn chilly as the winds can be very strong.
The locals have started wearing lighter outer jackets and fewer layers. Females are baring more skin- shorts, flats and low neck tops.
We were out today wearing 2 layers and only donning our outerwear(fleece or wool cos lighter to carry ard) in the evening.
Be warned that days may be comfy when the sun is shining but may be extremely windy. Nights get chilly. As always advised, dress in light layers. A lot of shops still have heaters turned on full blast. So it can be awful indoors if your first layers are thick.
Hth fr fellow SG