May 23, 2017. Difficulty rose by +6.42% to 595.92B from 559.97B.
Change
+6.42%
New difficulty
595.92B
Period length
13.2 days
Network hashrate then (7-day)
4.2 EH/s
Bitcoin price then
$2,215
Hashprice then
$857/PH/day
The 2,016 blocks before it took 13.2 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 6.42%: a large adjustment. For every machine on the network that is a pay cut of the same size until the next retarget.