Stock market holiday closures: Crypto tends to correlate closely with the traditional stock market. So when markets are closed for holidays, Crypto trading activity usually slows down as well. That can lead to reduced liquidity with lower trading volume which can result in increased price volatility. Markets in the United Kingdom, Europe and Hong Kong are generally closed. This represents roughly 10% of global liquidity.
This includes the London Stock Exchange, Euronext and the Stock Exchange of Hong Kong.
More information about how traditional market opening times are correlated with Crypto can be found here.