Small Transport; Low Wing; 2 Recip Eng
Flight Crew Instrument; Flight Crew Commercial; Flight Crew Multiengine
Flight Crew Last 90 Days 50; Flight Crew Total 8000; Flight Crew Type 2500
Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
General None Reported / Taken
Human Factors
Since COVID-19 ZZZ has no Tower services from XA:00 hr to XJ:00 hr local time. I had taxied out for departures several times before XJ:00 with no need to ask for ground services because they were closed. I was delayed and in tight quarters to taxi out of FBO; then taxi out at XJ:15 and I forgot the time had lapsed and taxied out without taxi clearance.There is no excuse; just a timing issue on my part. There was no issues with other aircraft and everything went fine then I recognized what I had done and contacted the Tower for departure and all was a non event. I'll be sure of the time before I taxi in the future.
Pilot taxied without clearance because he thought Tower was still closed; but it was actually 15 minutes after the Tower had opened.