"The FAA has announced plans to temporarily adjust operating hours at approximately 100 air traffic control towers nationwide due to the coronavirus (COVID-19) pandemic. When choosing how to modify hours, the agency says it looked at hourly aircraft counts and safety during non-towered times, air carrier, air taxi, and special operations, the ability of the workforce to social distance and reduce exposure, savings of supplies, and infrastructure constraints. The FAA will continue to monitor traffic volumes at affected facilities and make additional adjustments as necessary."
avweb.com/flight-safety/faa-regs/faa-to-adjust-hours-at-100-control-towers/