As anticipated, the expected variation in the Bitcoin difficulty took place tonight.
The variations in the difficulty increase or decrease the ease with which the blocks are mined and, since the average time required to mine a block is proportional to the mining difficulty, these adjustments are necessary to keep the average time required to mine a single block around 10 minutes.
Due to the halving on May 11th, there had been a significant reduction in the hashrate, from about 130 Ehash/s to about 90.
This reduction of about 30% compared to the maximum peak had caused a lengthening of the time needed to mine the blocks, which after May 11th had increased to more than 12 minutes.
The difficulty varies only every about 2 weeks, so it was necessary to wait until May 20th before it was reduced.
However, the reduction was not particularly significant, as it was limited to a little more than -6% so that the block time per hour was still more than 10 minutes.
At this point, there are two scenarios for the next change, scheduled for early June.
Should the hashrate remain roughly the same as it is today, a further reduction in difficulty is expected, perhaps as much as 20%.
In this case, the block time would still exceed 10 minutes, with the consequence that transaction fees could remain high.
If, on the other hand, the recent reduction in difficulty were to convince some miners, especially those who had decided to stop mining after the halving, to resume mining, then the hashrate would increase, reducing the block time without the need for a further significant reduction in difficulty.
So far the difficulty reduction has not yet brought the average daily block time back to around 10 minutes, but it could do so in the next few days.
Otherwise, it will be necessary to wait until the beginning of June to have another reduction that will finally bring the block time around this figure.
If the block time remains high, then the transaction fees may remain high, while if the block time decreases in the coming days, then the fees may return to levels more in line with those before the halving.
Otherwise, it will be necessary to wait for the next difficulty reduction to have a lower block time and therefore more confirmed transactions, with a consequent reduction in fees.
