Sapporo Snow Festival Accomodation Tips

So I'm planning for a trip to Hokkaido next year to visit the 2019 Sapporo Snow Festival. When I read some blogs, they said that on that dates (early Feb) the accommodations (hotel and/or Airbnb) will be quickly booked. What I want to ask is, when is the right time to plan the accommodations for such big festival?

My experience, hotel reservation was done 6 months in advance.

I travelled to Sapporo during the 2017 Snow Festival. When I tried to book hotels on Booking in October 2016, 99% percent of the hotels are fully booked. But I managed to find vacant rooms on a Japanese hotel booking website.

And be ready to pay 3x what that room normally costs.

when is the right time to plan the accommodations for such big festival?
The sooner the better, no dilly-dallying. I reserved 6 months in advance when visiting the Sapporo Yuki-matsuri several years ago.

I have been twice, in 2009 and 2015. Both times I was able to find a decent deal with reasonable notice. The first time I booked just days in advance and was on a budget, so had to stay in a airport hotel. But the train took around 30mins and the hotel was good, so no problems there. The second time over I booked a few months in advance, but was able to find a city center hotel at a price I would describe as normal Sapporo hotel price. All the JR hotels were booked by then and probably most other hotels too. In any case, I would not say I have had any problems.