Deribit expires options daily at 08:00 UTC, with weeklies on Friday and monthlies on the last Friday - all at that same clock time. Daily settlement runs at 08:00 UTC too. It is the most reliably scheduled event in a market that otherwise never closes.
Why a fixed daily expiry matters
Pinning is the tendency of spot to gravitate toward strikes with heavy open interest as expiry approaches, because dealers hedging that gamma buy weakness and sell strength around it. On equities you can observe this roughly twelve times a year at monthly opex.
In crypto you can observe it 365 times. For anything built on base rates rather than intuition, that is the difference between a hunch and a sample. A study that takes three years to reach statistical weight on SPX reaches it in a month here.
What to look at into the print
Three things. Where the call wall sits relative to spot, since that is the strike with the most positive gamma above and the most likely magnet. Whether net gamma is positive, which says dealer hedging will damp moves into the expiry rather than extend them. And how much open interest actually expires - a quiet daily with little size behind it will not pin anything.
The trap is treating every expiry as significant. Most dailies are small. The Friday weeklies and the monthly are where the notional concentrates, and those are the ones where the pin is worth trading around.