Quick Answer
The Blue Moon peak is around 08:44-08:45 UTC on May 31, 2026, which is approximately 4:44-4:45 AM ET, 3:44-3:45 AM CT, 2:44-2:45 AM MT, and 1:44-1:45 AM PT.
For visual observing, your best practical window is usually moonrise through midnight local time, not only the exact peak minute.