Daytime in the US is the peak volume of users on the market. Same thing happened last November during a surge in users. The site would slow to a crawl or be inaccessible during the the daytime and early evening US time, but it was fine at night and in the morning. Now the Tor network is congested with 2 million new clients, making most hidden services difficult to access, but that is compounded by the daily surge in SR users in the daytime.