This could be result of next halving cycle thats coming close day by day. It might be that various farms are restarting themselves and adding up the power of "lost china" miners when it was banned recently and full operations were closed down. That is pretty big difference which was balanced out by rest of the world miners, however it seems slowly they are building back with other miners. Every miner knows this is amazing opportunity to gain more coins in the wallet as they reach to the another halving cycle and thus aftermath is risen prices. This is helpful for them to profit the most during the high tide wave and keep the mining operations running smoothly. It's really a tug of war, the more we go ahead in the time, the higher hashrates would be there.