I did some preliminary research. Hokkaido peak is summer, during ,their lavender season. But also alot of visitors during the snow festival.

Assuming i want to do both snow festival and drift ice in next year feb, is it too late if i only start planning/booking in december? Ie 2 months in advance? 4 of us going. Just friends, and we are ok with ryokan/budget accom, flexible.

Thanks. Cause i'm abit lazy to plan right now and also not too sure about work load at this point in time.

I found an itinerary recommended on japan-guide.com. So i hope to catch the end of snow festival proceed straightline then end my trip on the east/northeast coast. Then back to my starting point and fly back to kl. I assume their itinerary suggested is realistic and not overly rushed.

Did you google on the right area that you are visiting? 10 to 20 sounds abit warm during mid november.

if its 10 to 20... a jacket over a tshirt should be fine. jacket with pockets to put your hands in there, if it gets too chilly...

i personally never tried heattech but it didn't work when people i went to beijing with suffered tremendously by relying on uniqlo (but that was around 0 C)